,,photo-,,lithography ,illustration ,,by ,,georg ,,fritz ,vice-director of the ,court and ,imperial ,state ,printing ,works at ,vienna ,,translated ,,by ,e4 ,j4 ,,wall 7,fellow of the ,royal ,photographic ,society7 ,author of 8,the ,dictionary of ,photography10 8,carbon ,printing10 etc4 ,illustration #ahie ,,london ,,dawbarn ,,and ,,ward1 ,,limited #f1 ,,farringdon ,,avenue1 ,e4,c4 ,,the ,,author',s ,,preface4 ,photo-lithography1 with its many branches and its extended application1 when used direct and also as handmaid for the lithographer and printer from stone1 is1 with the exception of phototypy and autotypy1 indeed that process for the preparation of letterpress plates which has done the most towards making photography useful for the graphic arts1 in the artistic sense as well as from the practical point of view4 ,and in the near future it will be a great acquisition when it is once generally recognized that colour plates can be prepared by photographic means without any considerable amount of manual or artistic help4 ,it is the more to be wondered at that photo-lithography has not yet found that extension and general use which it in so high a degree deserves4 ,i have written this book1 impressed with the urgency of stimulating the propagation of this useful process4 ,in writing ,i have been careful to avoid all those details which are for the practical worker of minor interest--the description of the historical evolution1 etc41 so instructive as these must certainly be--so that ,i have abstained from many complicated and unintelligible formul4 ,i leave this willingly to a more ready writer4 ,starting rather from the standpoint of speaking as a practical worker to practical men1 ,i have recorded all the experience which ,i have gained in the course of many years4 ,should it occur to me in the future that it was my task to have treated all photo-lithographic processes1 with all their ramifications1 in the most complete manner1 ,i have still the consciousness of having described as completely as possible the practical processes1 and think that ,i have thus been useful to many workers1 #b and ,i dare say with absolute certainty that only tested and tried formul have been noticed in this book4 ,with the earnest wish that this book may be received with a fraction of the goodwill with which ,i have worked at the writing of the same1 ,i present it to the technical world4 ,,georg ,,fritz4 ,vienna4 99 99 99 99 99 ,on receiving this work for review ,i was greatly struck with the thoroughly practical manner in which it was written1 and thought that an ,english translation might be acceptable to the large and ever increasing class of photo-mechanical workers who might not otherwise have the opportunity of reading it in the original4 ,i have kept to the author's text as close as is consistent with the idiomatic construction of ,german4 ,i am indebted to ,messrs4 ,hazell1 ,watson and ,viney for permission to undertake the task of translating the work for another firm of publishers1 and ,i hope the translation may prove as acceptable and useful to the readers as it has been pleasurable to me to do it4 ,e4 ,j4 ,,wall4 #a1 ,creed ,lane1 ,london1 ,e4,c4 #c ,,introduction4 #a4--,the theory of printing from stone4 ,he who would study or practise photo-lithography must first become acquainted with the fundamental principles on which lithography rests4 ,i find it therefore necessary to first give in concise form a small treatise on the theory of this process as well as on the most important materials which are necessary in the practice of the same4 ,the theoretical principle of lithography is purely chemical1 and is based principally on the repulsion of water and other substances by fatty bodies1 and the alteration of these greasy bodies by acids4 ,as the support for this chemical opposition a stone or zinc plate is used1 which are sufficiently porous to allow grease1 water1 acid1 and certain resinous solutions to penetrate to a certain degree4 ,the fatty substances which are transferred to the stone by writing1 drawing1 or transfer1 are autographic ink1 lithographic ink1 and chalk1 the so-called transfer and photo-lithographic colours4 ,there are also other substances1 which are used especially in photo-lithography1 which do not evidently penetrate the stone and which cannot be considered as greasy substances1 but which1 as we shall see later on1 have exactly the same action4 ,the above-mentioned fatty substances actually penetrate the porous stone and make it in places suitable to take more printing ink4 ,by the so-called etching--dilute nitric acid mixed with gum water--two effects are produced4 ,on the one hand the fatty bodies are altered in chemical composition1 being decomposed into the fatty acids which combine intimately with the material of the stone--calcium carbonate4 ,on the other hand1 the surface of the stone not covered with the fatty substances is chemically changed1 since the carbonate of lime is converted into nitrate1 which has now the property of keeping moderately damp when moistened with water1 and thus repelling grease4 ,if such a transfer of greasy bodies on to the stone is allowed to act for some hours1 and the fatty substances are removed with turpentine1 it will be seen that these places have a lighter colour than the other parts of the surface of the stone1 and if the stone be rolled up with a leather roller1 charged with a greasy ink1 after the stone #d has been damped1 only these places will take the greasy ink4 ,by means of a litho steam or hand press prints can then be prepared from this4 ,it is frequently necessary to make corrections or additions to the drawing on the stone2 if the stone has been already etched some means must be used which will remove the action of the etching1 or else the stone will not take the greasy matter1 or at least not so readily as is desirable4 ,very weak acetic acid1 about #a-b per cent41 will do this4 ,if the stone is flowed over with this dilute acetic acid or dilute table vinegar1 the action of the stronger nitric acid and the gum is stopped1 and the surface of the stone will again take fatty matter4 ,before the penetration of the grease the stone is prepared by polishing with a concentrated solution of oxalic acid4 ,oxalic acid poured on to the stone would exert an etching action1 but make the stone to a certain degree capable of taking the ink4 ,if this liquid is rubbed on the stone with a cloth or linen pad with moderate pressure1 the stone receives a high polish--especially the hard kinds--and in this condition the stone takes the ink well1 like any flat object1 but will not retain it4 ,if a transfer is made on to such a stone1 and the same etched1 the image will completely disappear the first time the roller passes over it4 ,this polish can be removed with #a or #b per cent4 acetic acid1 and the stone then has its primitive qualities4 ,this method is used to reverse the image1 which will be described later on4 #b4--,litho stone is dense limestone of the mountain limestone group1 and is found in the ,tertiary deposits at a depth of two to three metres4 ,its constituents are lime1 clay1 and silicious earths1 combined with carbonic acid1 but lime is in the preponderance2 it only contains a very small proportion of silica4 ,in the stronger acids litho stone dissolves completely4 ,the varieties of very fine stalactitic chalk of tolerable hardness1 with flat shell-like fracture1 without rust spots1 glassy crystals or impurities1 and those with very even grain1 are the most useful for photo-lithography4 ,marble1 which consists of pure chalk1 cannot be used for lithography because1 on account of its greater density1 the greasy matter cannot penetrate so deeply1 and therefore such stones would give only a few pulls4 ,the commercial litho stones are of different colours1 from whitish yellow to greenish shining grey4 ,the latter has a finer and more even grain1 and is considerably harder than the other kind4 ,these two kinds are briefly designated in the trade as 8yellow0 and 8blue10 and the brighter kinds are1 as a rule1 softer and cheaper than the darker4 ,the faults which the stones sometimes show differ considerably1 and these produce certain inconveniences in continuous work4 ,many stones have dark and light spots1 and as these spots have1 as a rule1 different densities1 the etching solution cannot exert the #e same action over the whole of the stone1 and consequently in fine drawings1 autotypes1 etc41 there are formed bright and dark spots4 ,this also occurs with calcareous1 speckled1 and marbly stones4 ,the very bright stones have less density1 and therefore suck up the damping solution very quickly1 and begin with repeated printing to become tinted4 ,stones with calcareous1 rusty or other veins split easily1 especially in the large sizes4 ,lime spots or lime veins1 which are easily recognized by their brighter colour1 take in graining a very unequal grain4 ,the drawing is darker on these places1 since the grain is greater according to the softness of the stone4 ,such stones are unsuitable for those photo-lithographic processes in which graining is used1 such as the processes of ,orell and ,fssli and ,barts4 ,the so-called glass veins and glass spots are crystallizations consisting of silicon1 and are harder than the other parts of the stone4 ,on these places the fatty inks do not penetrate deep enough1 and the drawing does not adhere well1 and can be easily removed by the rollers4 ,the hard stones receive a much finer surface than the soft when polished with pumice stone2 they also reproduce every point1 line1 and detail of the drawing much more delicately1 finer1 and sharper2 and1 lastly1 they have the advantage that they etch much more evenly1 and re-etching is easy if moderate care be taken4 ,for the finer photo-lithographic work1 if quality and continuous working is desired1 only the good 8blue0 stones should be used2 for cheaper line drawings 8yellow0 stones free from faults may be used4 #c4--,the zinc plates are now coming into pretty general use instead of stones1 especially in large establishments4 ,although their treatment before and during printing is essentially different to that of the stones1 yet so far as regards this method of printing they come very nearly equal to stones4 ,at first smooth polished zinc plates were used1 but in consequence of some difficulty in using them1 and the great care necessary in choosing them1 they have been almost replaced by the prepared or oxidized plates4 ,zincographic processes differ essentially in the preparation of the plates4 ,in the one1 the plate is given a coating which has a similar composition to a litho stone2 in the other1 the plate is roughened and given a fine grain by a mechanical method1 such as the sandblast1 in order that it may be then oxidized by a chemical process1 with acids or alkalies4 ,all these processes are more or less advantageous4 ,the zinc plates cost about one-tenth to one-twentieth of the cost of the stones1 and this may well be sufficient grounds for the proprietors of large establishments being interested in zinc plates1 as the stones are rather costly4 ,excellent zinc plates1 coated with a film or merely oxidized1 can be procured commercially in ,germany and ,austria4 ,for those #f who wish to prepare their own plates the following tested formul are given3-- ,a zinc plate from #a to #ae mm4 thick is roughened by means of the sandblast till it has a fine1 even grain and appears smooth1 but clean4 ,the following solution is prepared3-- ,concentrated solution of alum #bj parts ,phosphoric acid #b parts ,water #bj parts or ,alum solution #aj parts ,gallic acid #ae parts ,nitric acid #b parts ,water #cj parts ,the roughened plate is first flowed over with water1 and immediately afterwards1 with one of the above solutions1 in the same way as a plate1 is covered with a developer4 ,the plate is oxidized by this1 and there is formed on the surface a white precipitate4 ,it is then washed thoroughly under a rose tap and dried1 and the plate may be either coated with a light sensitive substance for printing or a transfer be made on to it4 ,after the development or the transfer1 the plate is gummed and then etched with an etching solution consisting of-- ,gallic acid #aj parts ,phosphoric acid #b parts ,gum solution #aj parts ,water #cj parts this being allowed to act for #cj or #dj seconds4 ,for repeated printing one to two per cent4 of gallic acid is added to the damping water4 ,if the plate has been correctly treated the print or the photo-litho transfer will furnish thousands of good impressions1 just like a stone4 ,further details as to the printing on the zinc plates1 or the transfer of the chromated gelatine prints on to the same1 will be found in ,chapter ,,iv4 #d4--,the greasy drawing materials which are necessary for lithography are litho tusch1 autographic ink1 and fatty chalk4 ,the two first are used in the liquid state1 the chalk1 however1 in solid form4 ,the ink can be obtained in a liquid form and the two others in solid state4 ,all three materials consist principally of soap1 tallow1 wax1 resin1 and soot4 ,soap and tallow give the necessary grease1 wax and resin give hardness and consistency1 and soot the colour4 ,the proportion of grease in the drawing materials must be so great that even the finest lines or points of a drawing can be well transferred to the stone1 so that they may not be attacked by the proper etching solution1 and do not break away from the stone by continuous printing4 ,as much black as possible in the drawing materials is pleasant for the draughtsman1 but is not actually necessary for this particular purpose4 #g ,the tusch must dissolve well in distilled water and flow fine and clean from the pen4 ,it should be tolerably brittle1 and the fractured surfaces should be shiny4 ,the photo-lithographer will frequently require the lithographic tusch for additions or for corrections4 ,the best is the so-called ,lemercier's tusch1 which is used in nearly all works4 ,it consists of-- ,yellow wax #b parts ,mutton tallow #b parts ,marseilles soap #f parts ,shellac #c parts ,lamp black #a-b parts ,these ingredients should be melted together by boiling4 ,the autographic ink is1 as a rule1 used for drawing or writing on paper1 and the result is then transferred to the stone4 ,instead of this1 any litho tusch can be used1 but for some work the autographic ink is more advantageous4 ,this ink must be thin1 run easily1 but not patchily1 from the pen1 and must keep for a long time equal in quality and action4 ,it is very advantageous that specially-prepared paper is not required1 since this always makes the work more difficult2 firm1 hard writing-paper is quite good enough for this work4 ,the commercial inks generally possess these good qualities1 and if much is not required one will hardly care to prepare it oneself4 ,a good successful autographic ink which draws in brown may be obtained from the following formula3-- ,marseilles soap #aj parts ,tallow #aj parts ,shellac #ab parts ,yellow wax #ab parts ,mastic #e parts ,asphalt #d parts ,vine soot #c parts ,distilled water #abe parts ,originals prepared with this ink transfer as well immediately as after several months1 and ordinary well-sized writing paper can be used for drawing or writing on4 ,lithographic chalk is only prepared in the solid form for drawing on paper direct or on stone4 ,according to the nature of the work1 it is harder or softer1 fatter or leaner4 ,the hard kinds1 which are also usually leaner1 contain more resin and less fat2 the soft1 on the contrary1 more grease4 ,fatty chalk is composed of-- ,wax #cj parts4 ,marseilles soap #bd parts4 ,tallow #d parts4 ,shellac #a part4 ,lampblack #f parts4 #h ,lean chalk is composed of-- ,wax #ab parts4 ,marseilles soap #h parts4 ,tallow #b parts4 ,shellac #aj parts4 ,lampblack #d parts4 ,for lithographic work a greasy ink is required in contradistinction to ordinary printing ink1 which consists of linseed oil and lampblack1 which would be called 8lean40 ,for inking-up a photo-lithographic chromated gelatine print such an ink cannot be used4 ,in order to obtain a good result in transferring1 this ink must contain grease1 soap1 and resin4 ,any good transfer ink can be used for a developing ink1 as this is applied with a roller4 ,it usually consists of equal parts of tallow1 wax1 soap1 some resin1 and as much litho ink as all the other ingredients put together4 ,that prepared by ,c4 ,kampmann1 ,technical ,instructor in the ,k4,k4 ,lehr- und ,versuchsanstalt at ,vienna1 contains1 besides the above-named ingredients1 asphalt and gum elemi1 and works well in practice4 ,thin developing inks1 which are distributed with a broad brush or a pad1 can be prepared by diluting good transfer ink with equal quantities of wax1 benzine1 and turpentine4 ,a good developing ink must have the following properties3 ,when spread upon the print must give a clean1 sharp1 sufficiently dense impression1 which can be easily transferred to the plate or stone2 on the other hand1 the drawing ought not to spread4 ,the transfer should possess such resistance that1 without rolling up1 it should resist a slight etching4 #e4--,the behaviour of asphalt on stone or zinc4 ,when a stone or plate is coated with asphalt solution and exposed under a negative1 and then washed with turpentine1 the exposed parts remain insoluble1 and in this way photo-lithographs can be prepared4 ,the asphalt here takes the place of the fatty ink1 and is1 after printing1 so firm and hard that without any rolling or inking up it can be etched with a weak1 gummy1 etching solution1 which gives a cleaner1 sharper drawing than the other processes4 ,the asphalt and other light sensitive resins not only intimately combine with the stone or plate1 but chemically alter the surface of the stone1 and possibly in a more advantageous way than the greasy inks4 ,when a properly-exposed drawing on stone is1 immediately after printing and development1 treated for a long time with rectified or ,neustadt turpentine1 it is completely removed from the stone1 and it will be found that the drawing appears of a somewhat lighter colour than the rest of the surface of the stone4 ,if this is now inked up with a roller1 these places take up the ink without having previously come into contact with grease4 ,numerous experiments which ,i have made on various lines go to show that the #i chemical theory of lithography has found an important enlargement with the use of asphalt4 ,the following are principal conclusions to be drawn from my experiments3-- 7a47 ,the exposed asphalt1 whether this exposure is made by printing or whether a drawing is first made and then exposed to the light1 adheres more firmly to the stone or zinc plate than if it was not exposed4 ,an asphalt drawing prepared in the dark and inked up does not adhere to the stone1 and this may be explained in that the grease cannot act through the asphalt film4 ,insensitive asphalt behaves in the same way4 ,with correct exposure under a clear negative of about #bj degrees ,vogel1 and subsequent development and auxiliary exposure for about half to one hour1 the drawing adheres firmly to the stone4 ,if the image is to be washed off1 the turpentine must act for five to ten minutes on the film1 till the exposed asphalt has dissolved4 ,if1 after washing off1 it is inked up1 all the places take the ink well1 and the image appears clear and plain4 ,the image can only be destroyed by strong acids or alkalies1 which actually dissolve the stone itself4 ,from this it is clear that the prints neither require inking up nor strengthening in any other way1 and my experiments have proved that in all cases the prints are1 by this treatment1 clogged up1 and neither gain as regards a longer run nor in withstanding etching4 7b47 ,solution of asphalt1 to which oil has not been added1 behaves as described above2 if1 however1 oil is added to it1 it acts still better as regards the keeping of the drawing1 and the prints need no subsequent exposure4 ,too large an addition of oil has the disadvantage that1 in developing with turpentine1 the asphalt dissolves too quickly4 ,the images wash off and one hardly has time to examine4 ,the exposed asphalt1 to which oil has been added1 also dissolves very readily4 ,for the preparation of colour plates this point is of some importance4 #f4--,the etching and preparing solutions are those solutions which make the stone suitable or unsuitable for taking the grease or water4 ,generally these are acids and gum arabic1 either used alone or together4 ,of the acids the most important is nitric acid1 the purpose of which is to convert the surface of the stone into a nitrate1 so that the grease cannot penetrate4 ,this acid acts even when diluted very energetically on the stone1 and produces a fine grain4 ,hydrochloric acid exerts a less energetic action2 it leaves the stone smoother and does not attack it so evenly as nitric acid1 but has the same result finally4 ,sulphuric acid ought not to be used for etching stone4 ,it forms calcium sulphate on the surface of the stone1 and this separates from the stone in printing and spoils the pulls4 #aj ,phosphoric acid may be used for etching as well as for preparing the stone2 it exerts a very faint etching action and is seldom used for this purpose1 but principally for making corrections4 ,acetic acid plays a very important part in lithography4 ,it possesses the property1 even in very dilute condition1 of stopping the action of the gum and oxalic acid1 and1 indeed1 even that of the stronger nitric1 sulphuric1 and hydrochloric acids4 ,it finds1 therefore1 considerable use in negative printing1 in making corrections1 etc4 ,it converts the stone into its original condition and makes it suitable again for taking ink4 ,citric acid fulfils the same purpose1 but is1 however1 much higher in price4 ,oxalic acid is not used for etching1 but only for preparation of the stone4 ,by rubbing the stone with a solution of oxalic acid with a pad of cloth it takes a mirror-like surface or polish1 into which the fatty ink cannot penetrate4 ,it is used for preparing the stone for lithogravure1 negative drawing1 and negative transfer1 etc4 ,tincture of galls1 or instead of this1 what is simpler1 gallic acid1 is used in lithography4 ,it contains plenty of tannin1 and is one of the most efficacious means of preventing the combination of the stone or zinc plate with fatty substances4 ,gum arabic or some other vegetable gum is indispensable for litho and zincography4 ,a #aj per cent4 solution of gum is generally used4 ,it penetrates all the pores of the stone and the plate1 and gives the same a thin but very firm film1 and prevents the ink taking on these places4 ,if it has become slightly acid it acts as a weak etcher1 and as an addition to nitric acid it makes the same of thicker consistence and more easily distributable4 ,the action of gum can be removed with acetic or citric acid2 with water alone this cannot be perfectly effected4 #g4--;,etching the stone4 ,there are two principal etchings1 the simple ordinary or first etching1 which obviously has the purpose of giving the drawing the necessary stability and protecting the blank places from taking ink1 and the deep or sharp etching gives for combination printing a still greater lasting power1 and for large runs keeps the drawing clean and sharp4 ,the ordinary etching chiefly causes the fatty substances to assume a new chemical condition1 since in combination with the stone they form insoluble fatty salts of lime1 which represent the printing surfaces4 ,it has1 however1 also the property of cleaning the blank stone surfaces from any adherent grease1 and makes the blank parts of the stone incapable of taking ink2 also it makes the drawing clearer and more precise4 ,the strength of the first etching may differ1 according to the following circumstances3-- 7a47 ,the stone2 for hard stones stand a stronger1 and soft stones a weaker etching4 #aa 7b47 ,the printing image2 fine drawings must at first be etched with a weaker solution2 coarser drawings1 on the other hand1 will stand a fairly strong etcher4 7c47 ,the material with which the print or drawing has been prepared2 very fatty developing inks and asphalt stand well even with strong etching1 whereas with lean or hard inks only a weak etching should be used4 ,an etching solution which is at the limit of strength1 but still suitable for a hard stone or a very coarse drawing1 would irretrievably ruin a very fine drawing on a soft stone4 ,commercial acids differ considerably in strength1 and it is1 therefore1 better to use a hydrometer than a measure4 ,it is also always more satisfactory not to use the acid by itself1 but in conjunction with gum4 ,a solution of gum of eight to ten degrees strength is diluted with nitric acid till it measures #aj to #ab degrees on the hydrometer4 ,this solution may be safely used for every case1 and it is only necessary to allow it to act longer for coarser drawings2 it should be evenly distributed over the surface of the stone with a clean soft pad4 ,in very hot weather it acts more energetically1 and then it should be used weaker for fine work4 ,in any case it is advisable to let the stone or plate stand for some hours before etching1 so that the ink may thoroughly combine4 ,the etching of zinc plates will be more fully described later on2 in other respects the treatment is the same as for stone4 #h4--;,deep-etching process4 ,the idea of this is chiefly to increase the printing form and to make the stone more resistant in printing4 ,in working this the principal thing is to sufficiently protect the drawing from the action of the strong acid4 ,this is generally done by dusting with resin1 which has a low melting point4 ,there are two deep-etching processes which are chiefly used1 one in which the resin is melted with a spirit flame1 the other in which the same thing is done by ether vapour4 ,the procedure in each case is extremely simple4 ,in the so-called burnt-etching process1 which has been perfected by ,eberle1 of ,vienna1 the already etched stone ready for printing is rolled up with a very stiff printing ink1 not transfer ink1 and then the drawing dusted with the finest powdered resin4 ,the stone is then gone over with a cotton-wool pad and plenty of talc or ,french chalk1 and then well dusted off with a broad camel's hair brush in order to remove all traces of resin from the blank stone4 ,to melt the resin a spirit lamp with a side flame is used4 ,the flame is passed over the drawing1 and ought only to be allowed to act sufficiently long to make the resin combine with the ink1 which can be recognized by the drawing looking shiny4 ,if it has been melted too long the sharpness of the drawing is damaged4 ,after this the etching may be at once proceeded with1 and this is effected with a solution of gum to which #h to #aj per cent4 by measure of #dd per cent4 nitric acid has been added4 ,for fine drawings #d to #ab #f per cent4 of acid should be used4 ,in using this a fairly strong effervescence takes place1 which should not frighten anyone4 ,in the ether or cold-melting process exactly the same procedure takes place1 only that instead of melting with an open flame this is effected by ether vapour4 ,for this work a wooden stick of about #b mm4 thick is laid on two edges of the stone4 ,on another ruler1 which should be large enough to cover the whole of the stone1 and which should be covered with flannel or stout cloth1 ether is poured2 this ruler is laid on the others1 so that it forms a right angle with them1 and is slowly drawn over the surface of the stone4 ,the ether vapour falls on to the surface of the stone and dissolves the resin which thus forms the protective film for the deep etching1 which is done precisely as described above4 ,another melting process recommended by ,scamoni consists in pouring alcohol on the stone and then setting fire to it4 #i4--;,differentiation of the printing processes4 ,technically we differentiate the principal printing methods into three1 according to the method of production4 ,the first and oldest is the typographic or letterpress printing1 which is founded on the principle that every line or every point which ought to print must stand up on the plate1 and all those places which must appear white in the print must be sunken in4 ,the artistic effect is obtained by tones which are formed of individual lines or points1 which are closer together or further apart1 or else print finer or deeper4 ,in printing a forme or plate1 etc41 it must be 8made ready10 that is to say1 the pressure in printing must be so arranged for each part of the picture that on the lighter places or finer places less pressure must be exerted1 whilst on the deeper tones more pressure should fall1 according to their gradation4 ,this balancing1 which is technically termed 8making ready10 is effected by cutting out the delicate and building up the strong or dark parts on the overlay4 ,with a proper overlay the artistic effect of the picture can be much increased2 with a faulty overlay it can be quite spoilt4 ,in letterpress printing the artistic element lies in the making ready4 ,typographic prints are distinguished by the lines1 figures1 etc41 being somewhat pressed into the paper1 and show raised up on the back1 which is technically termed 8impression40 ,when this 8impression0 is very plain1 that is to say when the printing has gone pretty deeply into the paper1 it is advisable before reproduction to remove this by strong pressure4 ,the second method of printing is exactly the opposite of the first1 and is founded on the principle of printing from intaglio4 ,the lines and points which should print are cut mechanically 7by engraving or piercing7 or chemically 7by etching7 into the stone4 ,the etched or engraved intaglio plate represents a negative1 or a reversed wood-cut1 only with the difference that the lines do not #ac lay in the same plane4 ,in order to obtain an impression the ink is pressed into the cut-out parts1 and is wiped off from the surface of the plate4 ,by stronger or weaker wiping the print receives a stronger or weaker local tone1 which is of great advantage from an artistic point of view1 but which forms no small obstacle to the reproduction4 ,the impression is represented in relief on the paper4 ,according to the depth of the lines they take more or less ink1 and appear therefore raised up in the impression according to the amount of their depth in the plate4 ,reproduction photography has to reckon on this disadvantage1 for with a side illumination the raised up lines cast shadows1 and a correct negative does not follow4 ,by the third method1 lithography1 of which we have already spoken1 the impression lies generally flat on the paper like a drawing1 if a very strong deep etching was not used1 in which case it is also slightly raised4 ,in printing from the graver or from stone etching a faint relief is generally noticeable1 which is never so high as with copperplate printing1 and which is no important obstacle to making a photographic negative4 #ae ,,chapter ,i4 #a4 ,,general ,,notes ,,on ,,photo-,,lithography4 ,by photo-lithography we generally understand that process by which it is possible to prepare a printing plate or a stone by the aid of photography from any original1 whether it be a drawing1 a print1 or an oil painting1 either of the same size or smaller or larger than the original1 which can be reproduced in the lithographic press4 ,the main characteristic of this process is that either the original from which the reproduction is to be made must be prepared in distinct lines1 strokes or points1 or that any half-tone which may be present in the photographic negative must be broken up on the stone or plate into lines or points4 ,the basis for the preparation of a photo-litho is as a rule a photographic negative on glass or gelatine1 which1 as the word negative implies1 when examined by transmitted light1 must have all its tones reversed1 that is to say1 the drawing or the lines1 strokes or points which must in the print be black1 must look transparent1 whilst the other part of the negative which forms the groundwork must be covered or opaque4 ,if every photo-lithographic process was to be described in detail there would be a great many1 but actually they may all be classified according to two principal methods3-- 7a47 ,one1 in which the stone or plate is itself coated with the light sensitive substance and exposed under a reversed negative1 so that a reversed image is formed on the stone or plate1 which in printing comes in the right position1 and 7b47 ,the other1 in which paper or a very thin zinc plate1 provided with a light sensitive film1 is exposed under an ordinary1 that is not reversed negative1 and thus is rendered capable of receiving fatty ink1 and is then transferred to the stone or plate by transfer4 ,of the many processes which1 though differing in detail1 may1 looking to the final result1 be assigned to one or other of the above-mentioned principles1 there are two which have been especially tested in practice1 namely1 for the direct transfer1 as we will call it1 that process which is based on the light sensitiveness of asphalt or of an organic substance in combination with a #af chromium salt2 and for the indirect transfer1 that process which is founded on the light sensitive chromium salt in combination with gelatine1 or briefly on the light sensitiveness of chromated gelatine4 ,all other more or less complicated methods have disappeared from technical practice and have only the honour of being scientifically interesting and theoretically correct1 but for various reasons are not practically valuable4 ,it is indeed obvious that a discovery so important and useful to one of the principal departments of the graphic arts as lithography is1 and which may be called even more essentially capable of variation and multiplication1 and perhaps in its way also more artistic1 should call forth an earnest movement on behalf of the technical experts1 principally with the endeavour for simpler forms and extension of its powers of work4 ,this1 indeed1 has not always been attained1 and these attempts will therefore only be taken into consideration in this book as may appear necessary1 and all others will be passed over in silence4 ,the methods used by some experimentalists for direct transfer1 which consist in coating the stone with a solution of gelatine1 albumen1 or gum made light sensitive with a chromium salt1 and after exposure under a positive or negative1 obtaining a printing plate1 were in execution complicated and troublesome1 but in results fairly safe and satisfactory1 so that they are now more and more used in practice4 ,iron and silver salts have been proved as not very suitable for photo-lithography1 and at the present time for direct transfer asphalt is most generally used1 and latterly also organic substances rendered light sensitive by a chromium salt2 for indirect transfer chromium salts in combination with gelatine1 or chromated gelatine4 ,asphalt exposed to the action of light undergoes a chemical change which consists in its becoming less soluble in its original solvents4 ,this was known to ,nicephore ,nipce1 one of the discoverers of photography1 whose endeavours to produce images by the action of light were actually based upon this very property of asphalt4 ,he used for this purpose metal plates which were converted by a species of etching into printing plates4 ,in the year #aheb1 the well-known ,parisian lithographer ,lemercier1 in partnership with ,lerebours1 obtained a patent in ,france for a process by which they were in a position to obtain images on stone by the exposure of asphalt1 and thus reproduce the same by printing in the ordinary way4 ,they coated a lithographic stone with ethereal solution of asphalt1 exposed it under a negative and developed it with ether2 there remained behind then the parts which had been rendered insoluble by light and formed a positive asphalt image on the stone1 the outlines of which had the property of taking up greasy ink and with suitable preparation of giving an impression on paper4 ,such a stone was etched in the ordinary way with acid and gum1 and then it was possible to make as many #ag pulls from it as was desired in litho ink4 ,we have here a practical photo-lithographic asphalt process1 as it is at the present time practised with various modifications1 and which gave satisfactory results4 ,other resins besides asphalt may also be rendered sensitive to light1 and it is well-known that they also may be used with as good results as asphalt for photo-lithography4 ,that the good qualities of asphalt were even earlier recognized is proved by the fact that ,negr1 before the discovery of zinc etching1 exposed a copper-plate coated with asphalt solution under a negative1 washed out the places not affected by light1 electroplated these blank places in a gold bath1 then cleaned the plate and deep etched it with acid4 ,he obtained in this way an intaglio printing plate similar to an etching4 ,by using a positive with this process a relief or typographic plate may be obtained1 both of which processes are known as 8gold etching10 and were practised in the beginning of the '#ej's in the ,k4 ,k4 ,hof- und ,staatsdruckerei4 ,the asphalt which is used for photo-lithographic purposes must possess certain qualities1 of which the most important is as high a light sensitiveness as possible4 ,with ordinary asphalt success will not be attained1 since it is only slightly sensitive to light2 the so-called ,syrian asphalt is therefore generally used1 which after having been prepared is dissolved in chloroform and then benzole and oil of lavender are added4 ,professor ,husnik prepares an asphalt from which all constituents not sensitive to light have been extracted4 ,herr ,valenta produces his sulphurized asphalt4 ,both possess a far higher light sensitiveness than ordinary ,syrian asphalt1 and are specially suitable for photo-lithography4 ,the second1 and considerably more extensively used method for photo-lithography--a transfer process--is based on the light sensitive property of the chromate salts in combination with gelatine1 or albumen1 or gum4 ,that the bichromate salts possessed light sensitive properties1 and could be used for photo-lithography1 ,mungo ,ponton discovered in #ahci4 ,he printed on an ordinary paper1 which had been rendered sensitive to light in a solution of potassium bichromate1 drawings and silhouettes1 and obtained after fixing1 which was effected by merely washing in pure water1 brown images on a white ground4 ,later ,talbot found that the chromate salts in combination with organic substances under the action of light altered the property of the latter1 and particularly that exposed chromated gelatine became insoluble in hot water4 ,poitevin used this discovery for carbon or pigment printing1 and had produced in #ahee various pictures with this process4 ,poitevin discovered1 further1 that exposed chromated gelatine #ah would not swell up in cold water and took up greasy ink1 and therefore after exposure under a photographic negative a picture could be obtained exactly inversely corresponding to the tones of the negative2 and that these places affected by light could be inked-up and printed from1 or could be transferred to a zinc or stone plate1 and from this pulls could be prepared4 ,by this discovery photo-lithography and collotype were actually discovered4 ,led on by his success1 ,poitevin used later1 instead of gelatine1 albumen and gum arabic1 and prepared with these photo-lithographic prints1 which were transferred to stone4 ,if a solution of gelatine is mixed with a solution of bichromate of potash1 and a sheet of paper coated with this mixture and exposed1 or if the paper is first coated with gelatine and then bathed in a solution of bichromate of potash1 various chemical changes take place as the result of the action of light on the gelatine film1 which we will now consider4 ,as has already been mentioned1 glue or gelatine is insoluble1 and only swells up in cold water4 ,in warm water1 however1 the gelatinous substance dissolves completely1 and sets on cooling to a jelly4 ,if a suitable sheet of paper is coated with the warm gelatine solution1 either by floating or pouring it over it1 and it be allowed to set1 and if this film is now made light sensitive in a solution of potassium bichromate and dried in the dark1 we shall have a photo-lithographic paper which1 according to the greater or less quantity of the chromium salt used1 has a more or less intense yellow colour4 ,if the paper thus prepared is exposed to light under a negative1 or in another way if some places before exposure are protected by black ink or strips of paper1 the places affected by light become dark coloured and brown1 and at the same time they have lost their power of swelling up in cold water4 ,the whole surface of the paper1 that is to say the exposed and unexposed films before being laid in water1 are flat or in one plane2 if1 however1 the print is laid in cold water the exposed parts are not affected by the water1 that is to say they have lost the property of swelling and remain in their original plane4 ,the unexposed parts swell up and appear raised up on the print1 and thus make the drawing sunken in4 ,the exposed places have1 however1 now received the property of taking up and holding greasy ink1 whilst the unexposed have taken up water and repel greasy printing ink4 ,if the paper be exposed under a negative the drawing appears sunken in after development with water2 the other parts1 which must in printing appear white1 are raised up2 by exposure under a positive the reverse is the case4 ,if these prints are in any way1 either by rolling up or brushing over1 given a coating of greasy ink1 the ink only adheres to the exposed places and a print in greasy ink is obtained1 which1 like any other greasy impression1 can be transferred to a stone or a metal #ai plate1 which can be printed from direct1 or the transfer may be made on to a metal plate for relief etching1 that is to say for the preparation of a typographic block4 ,in ,poitevin's process the stone itself was coated with a light sensitive chromated film1 and exposed under a reversed negative4 ,after developing and careful preliminary preparation of the stone the ink only adheres then to the places affected by light4 ,this is also the case if the stone is coated with light sensitive asphalt1 and the same printed on direct4 ,after exposure the parts not affected by light can be washed off with turpentine1 benzine1 or linseed oil1 so that the stone is laid bare2 the places1 the parts of the drawing affected by light1 however1 are not dissolved4 ,if the stone is now prepared with the solution of gum as has already been described1 and then rolled up with an ink roller1 these places will take the ink1 and by etching1 etc41 the stone may be so prepared that the same may be printed from like any drawing or engraving4 ,by photo-lithography only line or grained drawings can be reproduced1 and half-tones1 as is possible with collotype and photogravure1 cannot be obtained4 ,now1 with the aid of autotypic transfers and the asphalt process on grained stones1 we have a perfectly satisfactory method of reproducing in an excellent manner half-tone drawings by the aid of photo-lithography4 ,photo-lithography in all its various branches of application is at the present time so perfected1 and rests on so comparatively a simple principle1 that a technical printer1 with very little practice1 experience1 and observation of the formul given1 can attain in very short time absolutely good results4 ,at the same time it must be said that frequently very great difficulties have to be contended with2 especially as regards the quality of the materials and negatives great care must be used4 #b4 ,,subjects ,,which ,,can ,,be ,,reproduced ,,by ,,photo-,,lithography4 ,the next question which arises is1 8,what can be reproduced or multiplied by means of photo-lithography80 ,the answer is1 8,according to the existing state of the technique of photography and the perfection of the transfer process1 everything40 ,any line or wash drawing1 any oil painting or other plastic object1 any photograph of living creatures or lifeless objects--briefly1 any photograph can1 under certain conditions1 be transferred to stone or a metal plate1 and from this any number of impressions in greasy ink be obtained4 ,before the discovery of the method of breaking up half-tones into points or dots1 only line drawings could be reproduced by photo-lithography4 ,since1 however1 it has been possible to break up half-tone into line or points or grain1 nothing stands in the way of reproducing by this #bj method any kind of original4 ,this breaking up of the half-tone into a regular or irregular grain can be effected by means of a crossed line screen in making the negative1 as in autotypic1 or half-tone1 block-making1 or independently of the making of the negative1 as in the asphalt process of ,orell1 ,fssli and ,co41 and in ,barts' process and various other methods4 ,the undesirable half-tone must1 however1 always be broken up in some way into the requisite points or lines1 as it is one of the characteristics of lithography that it is only possible to print from distinct figures on the stone4 ,lithography and letterpress printing produce impressions of sharply-defined lines or points1 each of which must form a distinct whole4 ,any tone which is lighter or not absolutely black must be formed by lines or points standing in close proximity to one another4 ,the tonality must be formed by stronger or weaker lines or points1 by black and white spaces1 or by more or less close line and point patterns4 ,an absolutely closed tone1 as in collotype or photogravure1 is not attainable with lithography1 and although numerous experiments have not been wanting to reach this end1 the same have hitherto been without success4 ,the half-tones are broken up and separated into solid printable points3-- 7a47 ,by the autotypic transfer1 which is effected by placing in front of the sensitive plate when making the exposure the above-mentioned crossed-line screen4 7b47 ,by the so-called asphalt process1 by means of preliminary graining of the stone before coating with asphalt and printing4 7c47 ,by means of the production of a grain on chromated gelatine4 7d47 ,by the use of a sand blast1 which is the chief point of ,barts' process4 7e47 ,by transfer of a close grating or network on to a polished stone1 which forms the basis of the litho-heliogravure process of ,general-,director ,chas4 ,eckstein1 which is included in photo-lithography4 ,all these methods have for their purpose the breaking up of the light tones into regular or irregular but separate points4 ,there are other methods besides those mentioned above which have the same purpose4 ,we generally distinguish two kinds of reproduction3-- 7a47 ,those from line drawings1 in which a negative is made without the interposition of a cross-lined screen1 and for which no other means is used for the production of a grain1 and 7b47 ,those from wash-drawings1 paintings1 photographs from nature1 etc41 in which reproductions the half-tones are either broken up into lines or points by the use of the screen when making the negative1 or by any of the other above-mentioned means after making the negative4 #ba 7,a47 ,,line ,,drawings4 ,by the first method the drawing must be prepared according to certain formula if a good negative is to be obtained which shall not require much after work and disadvantages for photo-lithography4 ,a poor original may cause a partial or complete failure of the work1 or at least cause much cost and waste of time2 therefore it appears advisable to pay the necessary attention to the original which is to be reproduced4 ,what a line drawing must possess which should be reproduced well by photo-lithography in order to give a good transfer on to stone we will now point out4 ,before all things should be noted that the paper must be pure white and smooth1 yet not strongly reflective and not too weak4 ,smooth white cards of medium thickness are the best to use4 ,since all lines of the drawing appear in the impression of the same colour1 there is not only no purpose1 but it may even be very disadvantageous to the reproduction when the draughtsman1 in order to increase the artistic effect of his work1 or to produce good perspective1 etc41 draws fine lines or other points in a lighter colour4 ,the striving of the artist for effect1 perspective1 etc41 so far as this is attained by lines or parts of a lighter colour1 has for this process of reproduction no advantage1 but1 indeed1 the disadvantage that by this the subsequent manipulations are rendered more difficult1 the whole work will turn out more costly and finally less satisfactory4 ,although from the present position of photography drawings in any desired colour can be reproduced1 yet it is most advantageous if the originals for photo-lithographic reproduction are drawn with fine black matt ink on smooth white papers1 and the principal point to which attention should be directed is that all lines1 even the finest1 should be a good black1 and should be kept of the same strength of colour as the other parts of the drawing4 ,the thick lines must be quite filled up like the shadow lines of a strong letter4 ,shading must be obtained by strong1 fine running lines quite separate from one another4 ,in this the single black lines must not be too strong1 and the white spaces in between must not be too narrow1 or otherwise when reduced in size the white interstices will disappear and will finally form a solid tone4 ,the laying on of a tone or wash is not permissible1 as even a light tone will appear in the reproduction as a black spot4 ,it is not permissible also to draw on the same original with inks of different blackness or consistency1 and even if a coloured ink be used the whole original must be prepared with one colour 7red1 dark blue1 green1 or brown71 and that as intense as possible4 ,when we start from the only true standpoint1 that every reproduction should be a reflex of the original as true as possible1 artistic effects have from this point of view no purpose1 since the printer in printing with #bb one ink is not in a position to give grey lines as well as black1 but can only give the appearance of everything in one colour only4 ,he is1 however1 able to give with the strongest line the finest with their own characteristics1 and can1 therefore1 in this direction attain the tonality of the original4 ,it is obviously1 therefore1 the artist's duty to draw in one colour1 and since for photographic reproduction black is the best1 that is to say ,chinese ink1 he will do well to completely lay on one side all other artistic materials or effects4 ,at the same time it should be noted that originals drawn in any other colour can be reproduced by photo-lithography1 but if the drawing is to serve no other purpose than for reproduction it is best to prepare it in black4 ,a further important requirement is that the drawing be sharply and cleanly worked1 and since the reproduction of a ragged or broken line cannot make a full smooth beautifully running line1 they will appear in the reproduction in the same defective way1 and then require at least tedious retouching or make the printing of the subject actually impossible4 ,if it is necessary to cross the lines in the shadows this must be done with great care4 ,the points of crossing must be clean and sharp1 and the ink must not run4 ,too close or too frequent crossing of the lines should be avoided1 and would produce a bad and different effect in the reproduction4 ,smudges or wrinkles in the original appear in the reproduction more intense and more vigorous1 and therefore it must not be forgotten to carefully avoid these1 also any tracing lines must be erased1 without1 however1 damaging the ink lines or rubbing up of the paper4 ,pencil and chalk drawings1 assuming that they are cleanly executed1 can be well reproduced by photo-lithography1 only they ought not to be smudged or inked4 ,erasure marks on pencil drawings appear in the reproduction as smudgy spots4 ,drawings of architecture for illustration or other purposes1 after consideration of these remarks1 can be well transferred without much trouble by photo-lithography on to stone or zinc4 ,in drawings of maps1 plans1 etc41 there are still some rules to be observed besides the above4 ,boundary lines or mountain ranges with fine hatching1 waterlines for large rivers1 seas or lakes1 as well as the introduction of figures1 are better left out of the drawing1 and can be afterwards drawn on the stone2 they will then be cleaner and sharper4 ,if all these details1 however1 must be introduced into the original drawing1 they should be executed in a pale blue colour1 which will not appear in the ordinary negative4 ,for plans with large letters it is better not to draw the latter1 which are frequently a lot of trouble1 but to employ the simpler plan of getting the titles1 writing1 legends1 explanations1 etc41 printed by a book printer on paper of the same colour as the original1 and stick them on the latter4 ,the same method may be #bc adopted when preparing railway1 postal1 and telegraphic charts or maps with a lot of names or other titles1 etc4 ,the network of lines may be drawn with litho ink as suggested above1 but the names of the stations1 etc41 can be printed with letterpress and stuck on in the proper places4 ,working in this way not only will much labour be saved1 but at the same time sharper and more correct titles be obtained on the reproduction4 ,any necessary instructions for carrying out the drawing should never be made on the paper with red pencil1 but either with pale grey or pale blue4 ,for this paper rubbed with indigo or graphite can be used or a scratched gelatine proof which has been rubbed with finely powdered milori blue4 ,with commercial drawings it frequently happens that ornaments are repeated4 ,it is not necessary for the designer to draw all the ornamentation1 which may frequently be very complicated1 if it runs over the whole of the design4 ,it is quite sufficient1 according to the size or the number of times that the ornament occurs1 for the artist to draw it twice or three times1 or sometimes ten to fifteen times2 the lithographer will duplicate it by transfer4 ,this also applies if there is a border1 or if there are any corner or centre pieces repeatedly used4 ,it is quite sufficient to draw one-fourth of the frame or border1 or with very complicated designs a complete corner1 and to give the printer a rough sketch of the complete border4 ,he will make the necessary impression on transfer paper by photo-litho transfer on the stone2 he will also reverse the drawing from right to left1 join up the different parts1 and thus construct the whole border4 ,this applies also to the corner and centre piece4 7,b47 ,,drawings ,,on ,,blue ,,prints4 ,as a substitute for a proof cyanotype or blue prints may be used for preparing drawings for photo-lithography and other graphic arts4 ,when a photo-lithograph like a pen and ink drawing is to be prepared from a coloured picture1 or from a sepia or ,indian ink wash drawing of a plastic object or a photograph from nature1 or from an object not suitable for photographic reproduction an autotypic transfer is to be prepared1 a proof of the desired object must be first prepared1 and then from this the drawing is to be made4 ,it is obvious that the proofs of the first-named can only be made in the original size1 which under some circumstances may not be just what is required1 assuming that the original can be used in this way4 ,in all cases this will be inconvenient and tedious1 and possibly from the nature of the drawing many proofs be lost4 ,the end will be attained far more quickly and safely if a negative is made of the original1 either of the same size or enlarged according as may be desired4 ,the negative thus obtained is used to make a ferro-prussiate print4 #bd ,for this we use a good firm drawing paper1 which is sensitized in the following mixture3-- ,solution ,a4 ,potassium ferridcyanide #h parts4 ,water #aej parts4 ,solution ,b4 ,ammonio-citrate of iron #aj parts4 ,water #ajj parts4 ,when dissolved each solution is filtered and mixed in the dark room immediately before use in equal parts4 ,the solution thus formed is sensitive to light and is spread on a well-sized drawing paper as evenly as possible with a broad brush1 equalized with a distributing brush1 and then dried in the dark room4 ,the coated side of the paper appears yellowish4 ,it is then printed as usual until the deepest parts look grey1 as the prints look weaker after developing4 ,the prints are developed by floating them face downwards on a dish of pure water not too cold1 and then washed till the drawing appears quite white on a blue ground4 ,the washing must be thoroughly done or else the prints turn blue afterwards when exposed to light4 ,these prints contain all the finest details1 even in the deepest shadows1 plainly visible1 and will now be the most1 perfect and most convenient proofs for the artist4 ,the tracing or drawing is now done with good black dull surface ink as already suggested4 ,when the drawing is done it is allowed to dry thoroughly1 which will be in from two to three hours4 ,the following solution should be prepared3-- ,oxalic acid #a part ,water #aj part which should be poured into a flat dish and the drawing allowed to lie in it for about thirty minutes4 ,it is then again well washed and then immersed for fifteen minutes in a bath of ,hydrochloric acid #a part ,water #bj part ,the blue colour will now have disappeared1 and the ink drawing will appear pure black on the white paper4 ,it should be now hung up and dried in the ordinary way4 ,this drawing prepared in wash or line with ink now forms the original for a further photographic negative1 which is made in the correct size of the reproduction with or without the intervention of the crossed screen according to the character of the drawing4 ,with the negative thus obtained a photo-litho on stone or zinc1 or a typographic copper or collotype plate1 or a photograph on wood for xylography may be prepared4 ,the use of this process appears specially important for those cases in which an ordinary photographic negative is not sufficient1 #be for example where a printing plate cannot be prepared from the negative4 ,it ought also to be useful when the light could not be controlled in making the negative1 and thus incorrect effects appear in the reproduction1 which often occurs in negatives from nature and with polished plastic metal objects4 ,the enlargements from the original are then used because the details can be better seen1 and the artistic character can be more easily seen4 ,the fineness of the drawing must obviously be in proportion to the after reproduction1 while tones may be partly or entirely lost4 7,c47 ,,drawings ,,on ,,prepared ,,papers4 ,for photo-litho transfer without the use of a screen there are some commercial papers1 toned1 grain1 net or pyramid grained papers which may be used with excellent results4 ,on these papers1 according to their preparation1 various excellent results can be obtained1 which possess high claims as illustrations4 ,a smooth white scraper board made by ,angerer and ,gschl of ,vienna1 which has a very even film of chalk1 and which takes the lines clean and vigorously1 is especially suitable for pen and ink work4 ,on this paper plucky drawings like woodcuts can be executed4 ,the perfect whites of the paper1 combined with the vigorous beautiful black1 facilitate reproduction with excellent results and without much trouble4 ,an ordinary writing pen and ordinary ,chinese ink are used for drawing4 ,the ink gives sufficiently black and matt lines4 ,the deepest parts are covered with ink1 and the desired shading or stippling put in with the toothed scraper or engraving tool4 ,the shading off of the shadows may also be worked up with the toothed scraper1 and thus very delicate shading be obtained4 ,two more very useful papers by the same firm are known as scraper boards with printed lines or points1 and white scraper boards with simple or double lines stamped on to it4 ,these papers are also coated with a chalk film4 ,illustration3 ,fig4 #a4 ,with these papers the printed lines or dots serve as half-tones for the artist1 and by scraping with smooth or toothed scraper knives very many effects can be obtained4 ,lead pencil1 chalk or litho ink can be used for drawing4 ,for laying on1 ordinary ink with a small addition of soap may be used1 and new tone effects #bf may also be produced with a half dry ,chinese ink brush1 but for any drawing for line reproduction washing with paler or darker inks is excluded4 ,by scraping with the smooth scraper1 points are formed in place of the lines1 which by further scraping disappear entirely into white1 by which means the transit into the highest lights is effected4 ,if a black surface is scraped with the smooth knife a line tone is produced in the opposite direction to the printed one4 ,by the aid of the toothed scraper lines in any desired direction can be obtained4 ,when the printed tone is only desired in parts in the picture1 the other parts can be covered up with white paper4 ,the paper is only stuck down by the edges with mouth glue2 if it were stuck down all over with gum or starch it would be distorted4 ,on the white paper stuck on1 drawing may be done with the pen1 and thus new effects again be obtained1 as thus in a manner pen and wash drawing are combined4 ,the white scraper boards without printed lines or dots are either impressed with a single line or with lines crossed at right angles4 ,on this paper pen and ink drawings combined with grained tones may be done4 ,the outlines and everything which is to be treated like a pen drawing may be done with a hard pen or a marten brush4 ,bright tones are so worked with the brush that smooth surfaces are not formed1 but dotted darker or lighter tones4 ,those parts which have been laid on quite black can be brightened up afterwards with the smooth or toothed scraper knife or the needle1 and thus many gradations obtained4 ,instead of the litho writing ink pastell or very black good litho chalk may be used for drawing4 ,obviously this paper also ought not to be washed or smeared4 ,the pyramidal grain paper prepared by ,schuffelen of ,heilbronn is also very suitable for drawings for photo-lithographic reproduction4 ,the paper is coated with a chalk film of blinding whiteness1 and is stamped with a regular grain of truncated pyramids1 and is produced in three numbers4 ,grain ,no4 #a contains #b1ejj regular projections per square centimetre2 grain ,no4 #b contains #a1ejj2 and grain ,no4 #c1 #gej pyramids4 ,this paper is drawn on with litho chalk or black pastell crayons4 ,the deepest shadows are laid on quite black1 and light effects are introduced with the scraper or engraving needle as with the above described papers4 ,the same rules apply to the other parts of the drawing4 ,for drawing in general or the use of effects in drawing it should be noted that with all these papers the drawing may be somewhat overdone1 and this is necessary in order to obtain the corresponding vigorous action in the reproduction4 ,the printing ink is1 as a rule1 never such a deep black as the drawing ink1 nor is the paper which is used for printing ever so white as the lines of the toned paper4 ,the contrasts would1 therefore1 in printing become too #bg little1 and flat unsatisfactory pictures would be obtained4 ,with these drawings1 therefore1 the two opposites1 8black and white10 may be used to the extreme1 even if the drawing is not satisfactory to the artistic eye4 ,for making the drawing red paper ought not to be used1 as when photographed red appears dark4 ,then blue proof paper1 or paper rubbed with lead pencil1 should be used4 ,a drawing for photographic reproduction ought never to be rolled1 and still less be folded2 if it is to be sent away it should be packed flat4 7,d47 ,,reproduction ,,of ,,prints4 ,it is frequently required to make photo-lithographs of old prints4 ,as already mentioned in the introduction1 we distinguish three different methods of printing1 of which the two first1 typography and lithography1 are confined to the rendering of well-defined lines or points1 whilst copper-plate printing can to a certain extent reproduce lines and tones4 ,as regards the reproduction of the first two1 so far as their fundamental character goes1 no insuperable difficulties present themselves1 when they correspond at least to the general requirements of a drawing4 ,since a reproduction1 with exceptions1 can never be better--obviously without very complicated retouching--but always somewhat inferior to the original1 the appearance of the original will always be some guide as to the quality of the reproduction that can be produced4 ,if1 however1 prints are prepared specially for this purpose1 the following points should be observed3-- #a4 ,for printing a matt surface a so-called pure white chromo paper should be used4 #b4 ,the ink should be black and of good body1 the impression clean and sharp1 every line exact and not in the least fuzzy4 ,the expert lithographer will easily prepare his impression4 ,assuming that he has a good original stone1 he will more easily make good and correct prints from the engraving from the chalk1 pen or other drawing than the typographer4 ,the latter has to give his impressions the correct finish by means of overlays1 without the correct making and use of which no good picture1 whether it be characters or a drawing1 can be obtained actually on a typographic press4 ,the reader is referred to my article in ,professor ,eder's 8,jahrbuch fr ,photographie und ,reproductionsverfahren0 for #ahia1 where ,i have treated of this at length4 ,prints produced by the third method1 copper-plate printing1 give far greater difficulties to the photo-mechanical worker4 ,every pull from the engraved plate--etching scraper drawing and photogravure excepted--possesses a tone on its surface1 which is1 moreover1 very unequal1 and although increasing its artistic qualities1 offers1 however1 considerable difficulties for reproduction4 ,this can #bh only be avoided by very troublesome retouching1 which is frequently prejudicial to the beauty of the picture4 ,if pulls are specially prepared for reproduction the copper-plate printer must very carefully polish his plate and print without a tone1 but still this must not be done so that the plate is too strongly polished that the depths lose their vigour2 this would give an absolutely incorrect picture as regards gradation of tone4 ,etchings can1 as a rule1 only be reproduced with the aid of a cross-grained screen1 and the same applies to photogravures1 although the latter will seldom be required4 ,all tone or painted originals1 such as wash or sepia drawings1 photographs from nature1 collotypes1 photogravures1 water-colours and oil-colours can only be reproduced by photo-lithography by the interposition of a screen when making the negative1 or by a process in which the breaking of the tone is effected independently of the photographic negative1 and which will be described later on4 ,with old photographs which have faded it is as well to increase the lights and shadows by painting4 7,e47 ,,size ,,of ,,the ,,reproduction4 ,a question frequently asked is1 8,of what size should a drawing be made in order to obtain a good photographic reproduction80 ,this question cannot be precisely answered1 for a good deal depends upon the object itself1 and on the kind of drawing4 ,it may be generally said1 however1 particularly as regards pen and ink drawings on smooth paper1 that they should never be smaller1 only very rarely of the same size2 they should be drawn one-third or one-half larger generally4 ,the artist can execute fine details more easily and precisely on a large drawing than on a small one4 ,the enlarged reproduction gives any faults or mistakes which may happen to be in the drawing in proportionately larger size quite independent of the fact that an enlarged reproduction is always somewhat rough and ordinary4 ,reproduction in the same size reproduces the faults the same size as they exist in the drawing2 the reduction1 however1 also reduces the failings of the drawing if it cannot also absolutely remedy the same4 ,the reduced copy has always something finer and more delicate4 ,the degree of reduction must be kept in mind1 and the drawing be done with this in view4 ,if a drawing is executed very finely and full of detail1 and1 besides that1 contains very small lines of drawing or titles1 they do not gain in reduction1 but the opposite2 they lose1 as much that in the drawing appears plain and distinguishable becomes by strong reduction indistinct and unrecognizable1 or appears to the eye as a tone4 #bi ,individual cases1 in which for specimen purposes or to show how far reduction can go1 many times linear1 five1 six1 to ten times1 cannot be taken into consideration1 although the effect is usually well attained4 ,it should also be observed that the drawing must be considered not only as regards its size1 but also the strength of the lines and tones generally for reduction2 this specially applies as regards the tones4 ,by reduction the tone gradations are compressed1 the picture becomes poorer in tones1 and although1 theoretically considered1 light and shadow1 that is to say black and white1 are actually distributed in the same ratio as in the original1 yet the reduced image appears proportionately darker and loses in artistic effect4 ,great reductions will1 however1 be useful when for some special purpose such as the exact reproduction of geometrical figures or surface ornaments are required1 as for instance in printing designs for cheques1 bank notes1 etc4 ,in such cases the drawings should be made as large as is necessary for the most exact and easiest carrying out of the figures1 as in this way the precision of the drawing is better kept by reduction4 ,in such cases1 assuming that the ornaments are clear and open without shading1 the reduction may be carried beyond one-tenth linear4 ,this kind of reproduction should present no difficulties either to the reproduction or printing4 ,it is quite different1 however1 with drawings on scraper boards or grained paper4 ,if it is kept in mind that with too great reduction the gradations of tone of the print will be destroyed1 and that in the same degree the difficulties of printing will be increased1 care should be taken that reduction is not carried too far4 ,when it is further considered that in a reproduction with #b1jjj to #c1jjj points to the square centimetre the individual points disappear to the unaided eye1 and the different thick layers of points appear as closed tones1 the limit of reduction will soon be found4 ,if we reckon according to this view1 we can assume that those kinds of paper with coarse grain should be reduced at the most one-third1 those with a finer grain a sixth1 at the most a fourth1 in order to obtain good printing plates which will give large editions4 ,in this obviously will a good deal depend on the character and more or less rich in detail execution of the drawing4 ,still there are photo-lithographic processes such as the asphalt process of ,orell ,fssli ,co41 which contains about #ae1jjj points1 and ,barts' process1 which contains #aa1jjj points to the square centimetre2 still for reproduction in large quantities these processes offer many difficulties1 and cannot therefore really be taken into account when considering this4 #cj ,,chapter ,,ii4 ,,the ,,photographic ,,process4 #a4 ,,the ,,studio4 ,the arrangement of the reproduction studio is essentially different to that for ordinary portrait work4 ,the general points of such arrangements are described in detail in the handbooks of ,drs4 ,eder and ,vogel1 and these ,i may therefore omit so far as nothing novel is to be observed4 ,we distinguish now between daylight and artificial light studios2 further1 those in which a camera is used for making the negative and those in which a dark-room itself is the camera4 ,the first will1 of course1 be used where other things besides reproductions have to be made2 the arrangement without a camera presents many advantages for reproduction work only4 ,in the arrangement with artificial light the illumination of the object to be taken is effected as a rule with a source of light which can approximately replace daylight1 and which also remains as constant as possible1 and the electric light is at present the best4 ,although other sources of light are sometimes used1 the electric light in the form of the arc light for continuous practical use has the advantage4 ,for copying oil paintings daylight is to be preferred under all conditions1 and for this the best arrangement is the revolving studio4#a #a ,see ,eder's 8,jahrbuch fr ,photographie10 #ahic1 p4 #bca4 ,the description of a modern studio with electric light as used in the ,k4u4,k4 ,militar-geographischen ,institut in ,vienna1 and from which the studio of the ,k4,k4 ,hof- und ,staatsdruckerei was copied1 is given here4 ,this studio lies seven metres below the level of the street on the south front of the building1 and is shown in ,fig4 #b4 ,the preparation and dark rooms are illuminated with white1 yellow1 and red light by means of two #ej-;c4p4 incandescent electric lamps for each colour1 and besides this are provided with window screens of glass of the same colours for daylight4 ,the windows open into an area #ej cm4 wide which runs round the building4 ,the lighting is so arranged here that besides the ordinary collodion plates1 very sensitive gelatine plates can be worked4 ,the room ,c1 where the original is placed1 is fitted up #ca with four ,franzen arc lamps of #c1jjj c4p4 each for illuminating the original1 and the lamps are so arranged that the light falls centrally on the original4 ,the four lamps are fastened by ball ,illustration3 ,fig4 #b4 ,a is the room for the preparation of the plates1 for the wet collodion plates1 and the silver bath4 ,b the developing room4 ,c is the room in which the original is placed1 where is found a support for the original ,,tt1 as is shown in ,figs4 #c and #d4 ,d is the dark-room with the focussing table ,,ee 7,figs4 #b and #c71 and is separated from ,c by a wall of #ae cm4 thickness4 ,in this wall is found the photographic lens in a metal flange built into a stout iron box4 ,f is the washing and polishing room for the glass plates4 and socket arms to an iron frame which rests on rollers2 they can be raised or lowered on the frame1 and for taking small objects can be pushed closer together4 ,the arms are fastened to the round pillars of the frame1 being provided with a screw grip4 ,the lamps can be placed as close as #je m4 to the original4 ,as a rule1 however1 they are worked at a distance of one metre1 as then the intensity of the light is about equal to diffused daylight4 ,the axes of the carbons in the lamps are so arranged that the glowing crater formed in the positive pole is turned to the original1 by which means the illumination is intensified4 ,the positive carbons have a diameter of #bj mm41 the negative carbons #h mm4 ,the lamps stand in pairs one above the other at ,,ll4 ,in the two upper lamps the positive carbon is at the top and the negative carbon below it1 so that the light is equally distributed over the whole of the subject4 ,with this arrangement of the lamps all reflections are avoided1 and neither the grain of rough drawing paper1 the relief of an engraving1 nor the edges of pieces stuck on are felt4 ,the current is produced by a dynamo in the house2 it enters into the place at ,n1 whence it is divided into two circuits of #bj ampres1 in which are two switches1 an ammeter and a rheostat1 and the two lamps on either side4 ,the wall in which the objective ,o 7,figs4 #c and #d7 is placed1 as also the brick socle aa and ee 7,fig4 #b71 on which the support for #cb ,illustration3 ,fig4 #c4 #cc ,illustration3 ,fig4 #d4 #cd the original and the focussing screen rest1 run on rails1 and are absolutely isolated from the brickwork of the building in order to avoid any possible vibrations4 ,the stand for the original ,,tt is provided with screw fittings1 cams and wheels1 which make it possible to raise the original1 to lower it1 to move from right to left1 and vice-vers1 vertically and horizontally1 so as to place its centre axial with the optical axis of the lens1 as well as parallel to the focussing screen in the dark room4 ,the whole of the mechanism lies at the back of the stand1 so that there is absolutely nothing in front of the original4 ,the focussing table ,,ee is constructed in a similar manner to the stand for the original1 and is movable in every direction in the same way4 ,it carries in front two wood clips1 in which the board with the original is placed4 ,the table for the original1 like the focussing table1 is constructed on rollers1 which run on the already-mentioned rails4 ,in order to be able to fix these as soon as a sharp focus is obtained a brake is fitted4 ,the placing of the original table at the distance from the lens is accommodated according to the size in which it is to be reproduced1 and has already been estimated4 ,there remains1 therefore1 only to trouble about the fine focussing1 which is very quickly effected4 ,for taking line or wash drawings and for enlargements up to #hj #hj cm4 a ,steinheil wide-angle aplanat is used1 which gives no distortion4 ,the duration of exposure is with such subjects from eight to ten minutes4 ,for smaller subjects1 and principally for photographs on wood1 an orthoscope by ,voightlnder is used1 and the exposure varies from four to six minutes4 ,a ,zeiss anastigmat is used for making autotypes4 ,duration of exposure from three to five minutes4 ,coloured objects1 oil paintings1 etc41 are taken in the daylight studio4 ,they are printed in the daytime in the open air1 and in bad weather or under pressing circumstances in the night by the electric light4 #b4 ,,the ,,general ,,qualities ,,of ,,negatives ,,for ,,photo-,,lithography4 ,the negative for photo-lithographic work1 for whatever method it may be used1 must before all things possess two principal qualities2 when looked through it should be as clear and as clean as possible1 on the other hand the ground as well covered as possible4 ,the deposit must not be of a black colour2 from a well-drawn original absolutely satisfactory negatives can be prepared without the black colour4 ,when a drawing is reduced which contains grey lines1 dots1 and points1 as well as full black ones1 toned lines will be visible as well as the transparent2 with careful treatment1 the negative may be so far corrected that it may be used4 ,if this is not effected1 or is not possible1 the retouching on the stone will be somewhat troublesome4 ,the toned lines print later than the transparent2 these will therefore be overprinted #ce when the former have scarcely reached the correct degree of printing4 ,the choice is then only left either to weaken the lines which are too strong or to draw afterwards the faint or not printed lines4 ,if the ground is not sufficiently opaque it will print through4 ,this can be remedied by intensifying the negative1 or when this is not possible to paint over it as well as possible4 ,transparent spots are formed on the negative by an impure silver bath or by dust flying about the room4 ,these must be spotted out if increased work later on on the stone or zinc plate is not desired4 ,in reproducing fine copper engravings1 it generally happens that the fine grey hair-like lines and the light interstices1 if the plate was not properly polished1 appear less transparent in the negative than the other parts of the picture4 ,in developing the print the result is a partly broken image which can only be retouched with considerable trouble4 ,the negative can be corrected by taking care to paint over the transparent parts4 ,professor ,husnik recommends1 when the picture is not too large1 to fasten a transparent paper on the back of the negative1 and to cover over the glassy places with a soft lead pencil4 ,these parts then print simultaneously with the hair-like line and develop also equally4 ,if1 however1 the negative is large1 and the picture very complicated1 a glass positive picture is prepared in the following manner3 ,a polished sheet of glass is levelled and coated with the following solution3-- ,gelatine #f parts by weight4 ,sugar #a part by weight4 ,ammonium bichromate #a part by weight4 ,water #hj parts by weight4 ,when the solution has dried the glass plate is laid on the negative and exposed till the deepest shadows have printed1 and it is then developed in water4 ,when dry this glass positive is laid on the back of the negative so that every part of each picture fits4 ,the plates are then bound round the edges with paper strips so that they cannot shift4 ,by this--although somewhat troublesome--operation can an unsatisfactory negative be rendered more even4 ,this correction can also be effected in the following manner3 ,the back of the negative is coated with raw collodion which is faintly coloured with aniline red1 eosine or fuchsine1 allowed to dry1 and then with an engraving needle or a narrow knife the less transparent lines may be scraped out1 so that the red collodion only remains on the transparent places4 ,obviously also this can be done in the reverse1 by painting a faint red on the transparent places with a brush4 ,by this last method a tolerably extensive retouching may be #cf effected on unequal negatives1 which are the result of not quite equally black or also very close drawn originals1 from subjects with very fine lines1 such as copper-plate engravings1 or from finely-executed lithographs with very great reduction4 ,finally it should be mentioned that with intelligent retouching any bad negative can be used for photo-lithography1 and the only question now is whether it is not better to take the shortest way and prepare a suitable negative when the original really permits of its being done4 ,in printing on chromated gelatine paper a good result can be easier attained from somewhat foggy or thin negatives than by printing with asphalt or other light sensitive substance4 ,the following kinds of negatives are used for the various photo-lithographic processes3-- ,for the transfer process with chromated gelatine paper or direct printing on stone or zinc direct1 a reversed line or autotype negative4 ,for ,orell and ,fssli's process1 a reversed ordinary half-tone negative4 ,for ,barts' process and for photogravure on stone1 a direct ordinary half-tone negative4 #c4 ,,preparation ,,of ,,the ,,direct ,,glass ,,negative4 ,the preparation and cleaning of the plate glass is as follows3--,first of all the plates are roughened with a piece of sharp pumice stone on the extreme edges to the breadth of about #je cm4 in order to prevent the frilling or floating off of the collodion film4 ,this is very little trouble considering the advantage it offers4 ,after being edged the plates are placed in a solution of ,nitric acid chemically pure #a part ,water #aj parts ,instead of nitric acid1 chromic acid may be used1 but this is not absolutely necessary4 ,after one or two hours the plates are taken out of the acid bath1 well washed under a strong water rose1 and dried in a place free from dust4 ,then the plates are well rubbed with #a 3 #aj tincture of iodine solution with a pad of clean filter paper and then polished with #ej per cent4 alcohol4 ,this preparation must be done with absolute accuracy1 and thus they make all substrata of albumen1 india-rubber solution1 etc41 for direct negatives unnecessary4 ,plates which have been previously used are placed in pure water till the collodion film has become loose1 and are then scrubbed with a stiff brush1 treated for some hours to a bath of caustic soda1 and then treated as above1 when they may be used again4 #cg ,for reproduction of simple line drawings iodized collodion is used which consists of #b per cent4 raw collodion composed of-- ,ether #a1jjj ccm4 ,absolute alcohol #a1jjj ccm4 ,pyroxylin #dj g4 ,iodizing is done with ,sodium iodide #ae g4 ,cadmium iodide #ae g4 ,cadmium bromide #h g4 ,potassium iodide #a g4 ,the last salt is dissolved in a few drops of distilled water1 the other salts are dissolved in one part of the absolute alcohol4 ,the iodizing solution is filtered into the raw collodion1 which has already been allowed to settle and filtered1 and allowed to stand for some days4 ,the sensitizing solution is nitrate of silver in the proportion of #a 3 #aj1 with larger sizes #a to #ab-a to #ad1 and the silver bath is faintly acidulated with chemically pure nitric acid4 ,for a monochrome subject the exposure lasts according to the size of the reproduction1 and the rapidity of the objective1 from three to ten minutes4 ,for development an iron developer is used1 consisting of3-- ,water #djjj ccm4 ,ferrous sulphate #aej g4 ,copper sulphate #ge g4 ,alcohol 7#dj per cent47 #bej ccm4 ,glacial acetic acid #abe ccm4 ,the iron developer1 with addition of sulphate of copper1 is to be preferred for short exposures to iron and lead developer4 ,if the plate has been correctly exposed the image gradually appears after a short time1 and very soon gets vigorous4 ,when the details appear in the deepest shadows the development must be immediately stopped1 otherwise fogging will ensue4 ,if the image does not gain vigour by long development it was under-exposed2 with over-exposure the image appears quickly and remains thin4 ,the developer1 when fresh1 works fairly quickly2 older developers work slower1 but give very clear negatives4 ,for very fine line drawings or reproductions of copper-plate engravings the developer is used somewhat weaker1 and one-fifth of its volume of water added4 ,the development takes somewhat longer2 the fine lines remain1 however1 very clear4 ,after developing the plate is well washed and then intensified first with a solution of-- ,water #ejjj ccm4 ,ferrous sulphate #ahj g4 ,citric acid #ij g4 #ch to which a few drops of a #a 3 #ab silver nitrate solution have been added4 ,care should be taken that in the first intensification the glassy places remain clear4 ,when1 therefore1 the desired opacity is attained the plate should be immediately washed4 ,too long intensification fogs the finer lines4 ,the plate should be fixed with #e per cent4 solution of potassium cyanide4 ,for this1 however1 a concentrated solution of hyposulphite of soda can be used4 ,after well washing1 the negative will show1 when examined by transmitted light1 whether the ground is opaque enough1 or whether a further intensification is necessary4 ,with correct manipulation this first intensification will be sufficient for fine1 well-prepared drawings4 ,if1 however1 the opacity proves to be too little1 after thoroughly well washing1 the second intensification or blackening is effected with a concentrated solution of mercuric chloride in distilled water1 which is allowed to act till there is a distinct precipitate and the film has become grey4 ,after well washing the plate is flowed over with solution of thiosulphate of gold till the grey quicksilver precipitate has become absolutely black4 ,the gold solution consists of-- 7,a47 ,distilled water #ajjj parts ,chloride of gold #a part 7,b47 ,distilled water #ajjj parts ,hypo-sulphite of soda #aj parts ,immediately before use solution ,a is added with constant stirring to solution ,b1 and a few drops of ammonia added4 ,if the desired blackening is not effected with one application the operation must be completed4 ,the solution of gold1 when kept in the dark1 will keep a long time4 ,for fixed negative the following intensifiers have been used with good results3-- #a4 ,intensifier with pyrogallol4 7a47 ,silver nitrate #e parts by weight ,distilled water #ge parts by weight ,to this solution is added-- 7b47 ,citric acid #e parts by weight ,distilled water #ge parts by weight 7c47 ,pyrogallol #abe parts by weight ,distilled water #aej parts by weight #b4 ,the hydrochinone intensifier recommended by ,baron ,hbl3-- ,hydrochinone #aj parts ,water #ajjj parts ,to this as much acid is added as will keep the solution clear for #ci five minutes1 when it is mixed with a third of its quantity of #a 3 #cj solution of silver nitrate4 ,the addition of a few drops of sulphuric acid or #e parts of citric acid is generally enough4 ,this intensifier acts somewhat more delicately than the silver and iron solution1 and has the advantage over the pyrogallol that it can be applied as frequently as desired in full daylight to the fixed negatives without any danger4 #c4 ,the metol intensifier4 ,the negative should be developed with the above-mentioned iron solution3-- 7,a47 ,metol #ae parts ,citric acid #aj parts ,distilled water #ajjj parts 7,b47 ,silver nitrate #aj parts ,distilled water #ajj parts ,the negative must be fixed before intensification with hypo and well washed4 ,a small quantity of solution ,a is poured over the negative to drive off the water1 and then it is intensified in the ordinary way with #aj parts of solution ,a and #a part of solution ,b4 ,further intensification is effected1 as described1 with mercury1 the blackening with thiosulphate of gold4 ,when the negative is finished and dried it is coated with a solution of gelatine #a 3 #ej1 or a #a 3 #ae solution of gum1 in order to protect the film1 and the negative should be levelled and allowed to dry4 ,good opacity in the ground and clear glass in the lines of the drawing are the fundamental requirements of a negative for photo-lithography4 ,but drawings are not always prepared in such a manner that this can be completely obtained4 ,with flat drawings which are drawn in grey instead of black the first intensification is only continued till the finest lines appear clear4 ,for further intensification the negative after drying is given a coating of a light sensitive solution of-- ,gum arabic #age parts by weight ,white sugar #age parts by weight ,potassium bichromate #eh parts by weight ,glycerine #ah parts by weight ,water #ce parts by weight ,ammonia is now added till a light colour is formed4 ,after drying it is exposed from the glass side to #ae ,vogel's photometer1 washed for about a quarter of an hour and then soaked in warm water till a relief is formed4 ,by this operation a transparent relief is formed on the lines of the drawing1 which absolutely protects the same from fogging4 ,the intensification is then effected with mercuric chloride and chloride of gold1 or an intensifier of #dj solutions of uranium and ferridcyanide is used1 which is composed of two solutions-- 7,a47 ,uranium nitrate #h parts by weight ,sugar #h parts by weight ,water #cej parts by weight 7,b47 ,potassium ferridcyanide #h parts by weight ,sugar #h parts by weight ,water #cej parts by weight ,the negative is first flooded with the uranium solution and then with the red prussiate4 ,another process of intensification recommended by ,prof4 ,eder and ,toth is the so-called lead intensifier4 ,the somewhat under-exposed negative ought only to be developed with iron1 fixed with hypo1 and must then be well washed4 ,it is finally well rinsed with distilled water1 and then placed in a filtered solution of-- ,lead nitrate #d parts by weight ,potassium ferridcyanide #f parts by weight ,distilled water #ajj parts by weight ,after a few minutes it becomes absolutely opaque in the covered parts4 ,the negative is allowed to remain in the bath till it has attained the desired density4 ,on the silver molecules of the image a pale yellow precipitate has formed by the action of the lead bath4 ,the ferridcyanide of potash is reduced by the silver to yellow ferrocyanide of potash1 and gives then1 with the lead salt1 an insoluble compound1 ferrocyanide of lead4 ,by the action of ammonium sulphide the unstable lead salt is converted into a stable salt4 ,as soon as the negative has been taken from the lead bath and well washed1 till the washing water no longer gives a blue precipitate1 it is flowed over with dilute ammonium sulphide #a 3 #e4 ,sodium sulphydrate may also be used4 ,the image becomes black instantaneously4 ,the negative becomes generally vigorous2 if1 however1 it was exposed too long the fine hair lines and points veil over very easily4 ,if the negative is not sufficiently intensified1 which may happen with very much under-exposed negatives1 it should after well washing1 and before treating with ammonium sulphydrate1 be laid in a bath of-- ,cadmium sulphate #aj parts ,distilled water #ajj parts in which it becomes still whiter1 and should then be treated with the ammonium sulphide4 ,the lead1 the cadmium1 and the silver of the bath are converted by the ammonium sulphydrate into sulphide4 ,the negatives treated with cadmium have a yellowish tinge1 whilst those treated with lead are pure black4 ,for #da clearing up the white-lead image when it is too vigorous or is foggy hyposulphite of soda or a dilute solution of potassium cyanide can be used4 ,this manipulation1 however1 requires great care4 ,the negative treated with ammonium sulphide if foggy can be cleared up with hydrochloric acid1 used weak and repeatedly poured on and off1 with careful watching of the action4 ,after this it must be well washed4 ,the lead solution will remain clear for weeks1 and if it begins to work slowly can be freshened up with addition of lead nitrate and ferridcyanide of potash4 ,if stripping negatives are to be prepared1 it is advisable1 with the lead intensified negatives1 to give the glass plate a preliminary rub with vaseline oil1 to well wash1 and then to coat with raw collodion4 ,husnik's graphite intensification is still to be mentioned1 which1 in some cases1 may be of great service1 but requires practice and care4 ,the expert photo-mechanical worker will adopt one or the other methods for his work1 and as soon as he can work safely and without hesitation he will adhere to that4 #d4 ,,the ,,preparation ,,of ,,autotype ,,negatives ,,of ,,black ,,and ,,coloured ,,drawings4 ,as regards the preparation of autotype negatives from simple black originals--wash drawings--the above photographic processes are quite sufficient4 ,for taking painted originals--such as oil paintings1 water-colour drawings1 fresco1 and pastell drawings--an orthochromatic collodion must be used if a correct rendering of the tones in the negative is to be obtained4 ,in our studio we have obtained excellent results with two kinds of colour sensitive collodion4 ,these are the isochromatic collodion emulsion prepared by ,dr4 ,e4 ,albert and that suggested by ,major von ,hbl4 ,in using the former1 the glass plates as soon as they are taken out of the acid bath and well washed must be given a substratum of the following solution3-- ,white gelatine #e parts ,water #ejj parts to which is added-- ,glacial acetic acid #ae parts ,alcohol #aj parts ,the solution should be filtered and coated whilst warm1 and the plate dried in a room free from dust at least #ae ,r4 ,for the production of the sensitiveness1 or for the production of the correct reproduction of the colours1 two eoside of silver dyes1 ,r4 and ,p41 are used4 ,the ,p4 dye gives great sensitiveness1 and is especially suitable for portraits1 landscapes1 etc4 ,in using this a #db correct reproduction of the red must be abandoned1 whilst the ,r4 dye gives an absolutely correct colour rendering but requires about double the exposure4 ,ten ccm4 of the eoside of silver solution are added to #ajj ccm4 of the emulsion4 ,when coloured the emulsion will only keep for one or two days4 ,the time of exposure with the ,r4 dye is normally from one-and-a-half to three minutes4 ,after exposure the plate must be well washed under a tap and then allowed to thoroughly drain1 or otherwise developing streaks will show4 ,hydrochinone developer is used for developing1 consisting of three solutions3-- 7,a47 ,distilled water #ejj parts ,sodium sulphite #bjj parts ,potassium carbonate 7pure7 #bjj parts 7,b47 ,hydrochinone #be parts ,alcohol 7#if7 #ajj parts 7,c47 ,ammonium bromide #be parts ,distilled water #ajj parts ,this developing liquid is concentrated1 and is used as follows3-- ,solution ,a4 #ajj parts ,solution ,b4 #e parts ,solution ,c4 #g parts ,to obtain hard negatives solution ,b is increased from #a to #e times4 ,a mixture of #aej parts of the above solution with #ajjj parts of distilled water forms the actual developer4 ,by the addition of more concentrated developer or increasing the quantity of water the developer may be suited to the character of the subject4 ,the developer must be freely flowed over the plate1 and then the plate fixed with sodium hyposulphite4 ,intensification is effected with-- 7,a47 ,pyrogallol #g g4 ,citric acid #g g4 ,distilled water #aejj ccm4 and when dissolved ,glacial acetic acid #be drops are added4 7,b47 ,silver nitrate #aj g4 ,distilled water #ajj ccm4 ,immediately before use #ajj parts of solution ,a are mixed with #e parts of solution ,b1 and the intensification continued till the desired density is obtained4 ,negatives can be reduced by placing them whilst damp in a solution of-- ,potassium permanganate #a part ,distilled water #cjj parts ,when this has acted sufficiently1 the plate is well washed1 #dc flowed over with a five per cent4 solution of potassium cyanide1 and then well washed4 ,when the dyed emulsion is used this must be done1 after developing1 in red light4 ,a very excellent method of preparing an orthochromatic collodion emulsion has been described by ,hbl1#b which can be used either wet or dry4 ,repeated trials made in the ,imperial ,military ,geographical ,institute1 in our establishment1 and in the ,photographic ,institute in ,vienna have proved the advantageous use of this method for orthochromatic work4 ,the raw emulsion1 according to ,hbl1 is prepared as follows3--#dj g4 of silver nitrate are dissolved in #ej ccm4 of warm distilled water1 and as much ammonia added as will give a clear solution2 then #ajj ccm4 of alcohol are added and the whole allowed to cool4 #cj g4 of ammonium bromide are dissolved in #ce ccm4 of water and #gj ccm4 of absolute alcohol with gentle heat4 #b 8,encyclopdie der ,photographie10 ,heft #c1 and ,eder's 8,jahrbuch10 #ahib1 p4 #chg4 ,to make the emulsion #dej ccm4 of four per cent4 raw collodion are placed in a strong glass flask which will hold a litre1 and to this in the dark room the silver solution added4 ,some of the wool separates out1 but by vigorous shaking this can again be dissolved4 ,a part of the silver salt also remains suspended in the liquid in the form of fine crystals4 ,the ammonium bromide is added in three or four parts whilst warm4 ,after shaking thoroughly for several minutes the emulsion is precipitated by distilled water1 which is repeatedly added till the separation is complete4 ,the emulsion1 which is now powdery1 is placed on a linen filter1 washed several times with distilled water1 squeezed to press out the last of the water1 damped two or three times with alcohol1 and then pressed4 ,whilst still damp with alcohol the emulsion is dissolved in from #hjj to #a1jjj ccm4 of alcohol and ether1 mixed with #je grs4 of codeine1 and allowed to rest for some days1 when it will be ready for use4 ,the preparation of the eoside of silver solution is effected as follows3--#aj g4 of yellow-shade eosine are dissolved in #bej ccm4 of boiling water and #e grs4 of silver nitrate in #ej ccm4 of water added hot4 ,the solution is allowed to settle1 then filtered1 and then washed first with boiling water and then with alcohol on the filter1 and then dried in a dimly-lighted room4 ,to prepare the dye solution #je g4 of the dry eoside of silver and #a g4 of ammonium acetate are gently heated together in #cj ccm4 of alcohol till dissolved1 then #abj ccm4 of alcohol and #aj ccm4 of glacial acetic acid are added1 and the whole filtered4 ,for plates to be exposed wet1 #e-aj ccm4 of glycerine are added4 ,the emulsion is sensitized by adding one-tenth of its volume of dye1 and should be well shaken before coating the plates4 ,the glass plates should receive a preliminary substratum of gelatine or india-rubber1 so that the frilling of the film and impurities of the glass plates may be totally avoided4 #dd ,for small sized plates the emulsion is used somewhat thicker than for larger1 and for the latter it should be diluted with alcohol and ether4 ,after coating they should be dried at about #ae ,c41 and then for some minutes exposed to a temperature of #cj ,c4 ,the plates should be developed with the following mixture3--#be g4 of sodium sulphite should be dissolved in #dj ccm4 of warm water1 then #aj g4 of glycine added and #ej g4 of potassium carbonate1 at first in small quantities in consequence of the evolution of carbonic acid4 ,when cool about #ge ccm4 of a thin pasty liquid will be obtained1 which may be kept as a stock solution1 and before use must be well shaken and diluted with from #ab-ae times the quantity of water4 ,wet plates should be washed before development1 and the developer flowed on2 dry plates should not be washed1 and should be developed in a dish4 ,they should be fixed in sodium hyposulphite4 ,the intensification may be effected with metol 7see p4 #ci71 and the blackening as described on p4 #ch4 ,obviously the collodion emulsion may be used for ordinary work undyed4 ,the qualities of the cross-lined screen and the distance of the same from the sensitive plate will be described in ,chapter ,v4 #e4 ,,preparation ,,of ,,reversed ,,negatives4 ,for the different photo-lithographic work direct and reversed negatives are used2 for the transfer process direct negatives are used2 for printing direct on to the stone or plate1 reversed negatives4 ,for making the latter various methods are used1 the principal of which are as follows3-- 7,a47 ,,exposure ,,through ,a ,,prism4 ,this method is1 on account of its inconveniences and difficulties1 only used when it cannot be possibly avoided4 ,illustration3 ,fig4 #e4 #de ,fig4 #e shows the arrangement in which the prism a is placed in front of the lens b4 ,the prism is three-cornered and the angle turned to the objective is a right angle4 ,the hypothenuse is silvered4 ,it is mounted in brass or nickel2 on the mount is a screw1 by means of which it is fastened to the objective1 so that the side opposite to the hypothenuse lies upright to the side of the camera1 and this position must be an exact right angle to the focussing screen4 ,the camera itself must be absolutely horizontal4 ,the subject to be taken1 instead of being in front of the camera1 is placed sideways to the prism4 ,the image passes through a1 falls on the silvered hypothenuse a1 from there through the objective b1 through the box-shaped extension c and the camera d1 on to the sensitive plate1 which is not visible in the diagram4 ,the exposure with the prism is about #a_/eth longer than usual1 because a portion of the light is absorbed by the prism4 7,b47 ,,placing ,,the ,,plate ,,the ,,wrong ,,way ,,round ,,in ,,the ,,slide4 ,generally1 for making reversed negatives of line drawings1 it is quite sufficient to place the sensitive plate the wrong way round in the dark slide or in the carrier1 so that the film side1 instead of being towards the objective1 is turned towards the operator4 ,it is1 of course1 absolutely essential to use only glass plates which are absolutely clean and which contain no particles of sand1 air bubbles1 etc41 which would show on the prepared negative as points4 ,after sensitizing the plate1 the back of it must be thoroughly cleaned1 for any smudges or drops would be visible on the negative4 ,obviously great care should be taken also in cleaning the plate to make as little dust as possible4 ,in the ,imperial and ,state ,printing ,works nearly all the reversed negatives are prepared most satisfactorily in this way4 ,the photographic manipulations1 the preparation1 sensitizing and developing of the plates1 etc41 is exactly the same as with direct negatives4 7,c47 ,,stripping ,,negatives4 ,there are various directions for making stripping negatives4 ,an india-rubber solution1 consisting of equal parts of benzole and chloroform1 in which an equal part by weight of india-rubber is dissolved1 is used as a substratum4 ,when the solution has become quite clear1 the unreversed and unvarnished negative is coated with it4 ,when the film is dry1 a coating of raw collodion1 to which some drops of castor oil have been added1 is given4 ,when this film is quite dry1 it is cut through near the edges with a sharp knife1 and the glass plate and film placed in a dish filled with water1 when the negative film will loosen from the glass and after some time will swim in the water4 ,in this operation the use of force must be avoided4 ,the film is lifted from the water by placing a card #df underneath it1 carefully dried with fibre paper1 then laid flat and pressed somewhat between tissue paper4 ,the negative prepared in this way has many disadvantages4 ,first of all1 the film is easily injured1 and1 therefore1 the edges should be bound with strips of paper in order to protect it from tearing2 further1 the film is easily folded and does not remain accurately of the same size1 which makes it useless for certain purposes4 ,moreover1 this process is somewhat costly4 ,it is now almost entirely replaced by a process in which a gelatine substratum is used4 ,this process is as follows3--,the unvarnished negative is accurately levelled with a level and coated #b mm4 thick with a solution of-- ,white gelatine #bj parts by weight4 ,distilled water #ejj parts by weight4 ,glycerine 7chemically pure7 #be parts by weight4 ,glacial acetic acid #aj parts by weight4 ,alcohol #cf #ej parts by weight4 ,the above quantity is quite sufficient for at least four negatives #ba #bf cm4 ,many omit the acetic acid1 but ,i have found that it is an advantage for the slow drying1 the pliability1 and the keeping of its size of the negative1 to use acetic acid in moderate quantities4 ,to a certain degree the addition of glycerine also effects this1 but not sufficiently enough4 ,before pouring on the gelatine solution1 the plate must be absolutely dry4 ,any air bells formed whilst coating must be pushed to the edge of the plate with a piece of card4 ,the plate must be dried spontaneously in a room as airy and as free from dust as possible4 ,in order to protect the film from dust particles1 it is advisable to give it a paper cap or cardboard cover1 which allows the access of air1 and obviously it ought not to touch the film4 ,when the gelatine film has become thoroughly hard1 it should be coated with negative varnish1 and1 after again drying1 should be cut round the edges with a sharp knife right through to the glass and stripped from the plate4 ,if the glass was well-cleaned and prepared1 as has been previously described on page #da1 any gelatine film thus prepared will well and safely strip without a substratum4 ,with dirty or old plates1 a substratum of a #a-b solution of india-rubber should be used4 ,after stripping1 the gelatine films are best kept between filter-papers and under glass plates4 #dg ,,chapter ,,iii4 ,,photo-,,lithography ,,by ,,the ,,transfer ,,of ,a ,,greasy ,,print ,,on ,,to ,,stone ,,or ,,zinc4 #a4 ,,the ,,home ,,preparation ,,of ,,bichromated ,,gelatine ,,papers4 ,photo-lithographic or gelatine papers are articles of commerce and entirely fulfil their purpose1 and must before use be sensitized in a bichromate bath4 ,in establishments where much photo-lithographic paper is not used1 it is better to obtain it commercially from some reliable firm and not to make it oneself1 as this is somewhat troublesome1 and requires special appliances1 some practice and experience1 and with small consumption does not pay4 ,for those who are interested in the preparation of chromated gelatine paper ,i will now give the method1 and ,i would remark that this paper possesses all the necessary qualities for this process4 ,a sheet of well-sized paper is soaked in a bath of cold water1 or evenly damped with a clean pad1 till it has become slimy4 ,the water is allowed to drain off1 and then the sheet of paper placed on a plate of glass which has been accurately levelled1 and which rests on a levelling stand with screws1 so that it can be easily levelled4 ,by placing over it a sheet of blotting paper and squeegeeing with an india-rubber or flannel squeegee the air bells between the paper and glass are removed and any excess of water pressed out4 ,then the edges of the sheet are bent up to about the depth of #b cm41 and wood or iron rods laid outside1 and a warm #a 3 #cj gelatine solution poured on to it4 ,a sheet #gj by #gj cm4 will require #cje g41 that is #ge g4 of gelatine and #bige g4 of water4 ,the gelatine will set in a few minutes1 when the sheet is removed from the glass and laid on a rack in a place free from dust to completely dry1 and should remain from a day and a half to two days4 ,such gelatinized sheets can be kept in stock1 and will keep fit for use in a cool1 dry place for from six to eight months4 ,for this purpose only good pure rag paper should be used1 as the ordinary cheap papers contain many additions which render them unsuitable for this work4 7,a47 ,,the ,,gelatine4 ,the gelatine must possess certain qualities1 of which the principal are as follows4 ,before all things it must be pure and free from grease1 or else small round pits form on the surface1 which give rise to troubles in developing and printing1 and only produce #dh defective transfers4 ,a large proportion of carbonic acid will produce the same faults1 which may1 however1 be remedied by a small addition of ammonia shortly before use4 ,gelatine is very hygroscopic1 and therefore attracts moisture from the room where it is kept and dissolves completely in warm water4 ,even in very great dilution1 e4g41 #a 3 #ajj1 it sets again to a jelly in the cold1 but loses the setting power after being repeatedly warmed1 or if the temperature was raised considerably higher than was necessary to melt it4 ,damp gelatine decomposes in the air very soon2 the decomposition1 however1 can be delayed with salicylic and carbolic acids and glycerine4 ,greasy gelatine can be improved by the addition of #e per cent4 of alcohol4 ,too soft gelatine can be hardened with chrome alum1 and one part of chrome alum may be used to #bjj parts of gelatine1 and by this addition the melting point is raised about #g ,c4 ,too hard gelatine gives rise to the formation of bubbles4 ,if the gelatine solution is slightly acid it is not a disadvantage4 ,the gelatine used in our establishment is of ,french make1 and is known as 8transparent white gelatine10 and is also very suitable for collotype4 ,i mention this because the gelatine frequently gives rise to failure4 ,for practical work1 then1 it is advisable to stick to one make when it has been proved to be absolutely satisfactory4 ,to those who would study more closely this very important material for photo-lithography and collotype1 ,i would strongly recommend the brochure 8,ueber die ,reactionen der ,chromsuren und der ,chromate auf ,gelatine1 ,gummi1 ,zucker und audere ,substanzen organischen ,ursprunges in ihrer ,beziehung zur ,chromatphotographie10 by ,professor ,eder1 in which the most exhaustive information on the application of these two materials so important in photography1 gelatine and the chromate salts1 is given in a concise1 popular1 and easily understood form4 7,b47 ,,the ,,chromate ,,salts4 ,the sensitiveness to light of the different chromium compounds forms at present the foundation of several photographic and photo-mechanical processes4 ,according to ,dr4 ,eder1 ,vauquelin discovered in the year #agih chromium and chromic acid1 and made at the same time the observation that chromic acid formed with silver a carmine red salt1 which became purple-red by the action of light4 ,in the year #ahcb the philosopher ,dr4 ,gustav ,suckow1 in his work1 8,die chemischen ,wirkungen des ,lichtes10 stated that the chromate salts were also sensitive to light in the absence of silver if an organic substance was added1 as in the light lower 7green7 oxidation products were formed4 ,in #ahci ,ponton added to ,vauquelin's and ,suckow's discoveries1 and discovered the photographic application of chromate of silver1 the light-sensitiveness of potassium bichromate on paper4 ,the chromates are per se stable in light2 in the #di presence of organic substances1 however1 such as gelatine1 albumen1 gum1 etc41 a quick reduction of the same takes place in light4 ,talbot finally found that a mixture of gelatine and a chromate became brown in light1 and lost at the same time its solubility in warm water and its power of swelling up in cold water4 ,according to the same authority simple potassium chromate is from #bj to #be times less sensitive to light than potassium bichromate1 and the simple ammonium chromate shows the same sensitiveness to light as ammonium bichromate4 ,for photo-lithography the latter salt1 potassium bichromate1 is very important1 and it has the chemical formula of ,k#b;,cr#b,o#g4 7,c47 ,,the ,,gelatinizing4 ,the gelatinizing of the paper and the preparation of the gelatine solution is effected as follows3-- ,the gelatine1 accurately weighed out1 is placed in small pieces in the proper quantity of water1 either in a large measure or some other vessel1 and placed in a water bath and immediately heated4 ,it is advisable to place the vessel containing the gelatine into the water bath before the latter is heated1 so that both may heat together and fracture of the glass be thus avoided4 ,when the gelatine is completely dissolved the warm solution is filtered through a linen filter1 and so that it may not be cooled the vessel into which the gelatine solution is filtered is also placed in the water bath4 ,whilst still warm and liquid the gelatine is poured on to the previously prepared paper1 and any bubbles of air brought to the edge of the sheet with a strip of stiff paper or a feather4 ,it should be especially noted the gelatine solution should be used up as quickly as possible or else it will deteriorate4 ,gelatine which remains for a long time in a state of solution becomes soft and fluid1 and if the chromate bath is not well cooled a partial or complete dissolving of the same takes place in sensitizing or later in washing and developing4 7,d47 ,,sensitizing4 ,the first thing to be treated of is the preparation of the bichromate bath4 ,the necessary quantity of the bichromate of potash is rubbed up as fine as possible in a porcelain mortar with a little water2 it should then be transferred to a larger flask and the necessary quantity of water added4 ,when all the bichromate is dissolved the solution should be filtered1 and so much ammonia added as will convert the orange yellow colour into a straw yellow4 ,this bath can be kept1 in a dark cool room1 fit for use for a long time4 ,the proportions for the solution are-- ,potassium bichromate #a part ,water #ae parts #ej and as much ammonia as will make it straw coloured4 ,the bath is neutralized with ammonia or a soda or potassium salt1 because solutions of the bichromate salts have the property of dissolving gelatine even in the cold4 ,the day before being used the sheet of gelatinized paper is placed in this bichromate bath1 which should be as cold as possible2 in summer it should be cooled with ice4 ,it should be completely immersed in this bath1 so that the solution covers every part of the sheet to the depth of #a-b cm41 and should be left in it about three minutes2 care must be taken that no air bells form on the gelatine4 ,if this should happen they should be removed with a soft brush1 which ought not to be used for any other purpose4 ,on the places not covered by the bichromate solution1 which has been kept off by the air bells1 the paper would not be sensitive to light4 ,for ordinary printing the paper may be dried in the air by placing it on a board1 or better on a rack2 for better class work1 and actually for all work1 it is better to squeegee the paper as soon as it is removed from the bichromate bath on a sheet of plate glass which has been well cleaned and polished with talc1 the excess of solution or any air bubbles being removed by squeegeeing thoroughly under blotting-paper4 ,many operators slightly grease the glass plate4 ,i have found that this is not necessary if a sufficiently cold sensitizing bath is used1 the plate glass thoroughly cleaned and well rubbed with talc1 and it is dried in an airy room4 ,it is advisable to see that there is always ventilation in the drying room1 and the more this is done the better the paper will behave in the subsequent operations4 ,to completely dry1 the paper requires when drying by itself from three to four hours2 from ten to twelve hours when squeegeed to glass4 ,the best way is to sensitize the paper in the afternoon or the evening1 so that it may be used the next day in the morning4 ,the paper when sensitized will1 when properly kept in a dark cool room1 be in a fit state to use for several days4 ,by squeegeeing on to the plate glass the paper takes a very high glossy surface1 and thus in printing comes into intimate close contact with the negative4 ,in exposing1 therefore1 every fine line appears with greater precision than on paper which has become wrinkled and uneven1 and which has not been previously glazed4 ,it should also be mentioned that this gloss is frequently obtained by burnishing the sensitized paper when dry4 7,e47 ,,the ,,printing4 ,after the paper has been sensitized and well dried it is printed4 ,the negative is first laid in the printing frame film side up4 ,then the paper is laid with the sensitive yellow side on the negative1 and the frame closed4 ,before it is placed in the light1 care #ea should be taken to see that the paper lies closely everywhere on the negative1 otherwise it will in parts be indistinct1 and the print be useless4 ,for estimating the correct exposure a photometer should be used1 and ,i take as an example ,vogel's ,fig4 #f4 ,illustration3 ,fig4 #f4 ,when beautiful clear negatives are used they should be printed to #ad to #af degrees ,vogel4 ,obviously no strict instructions can be given for every case1 and it will be dependent on the quality of the negative and the object4 ,if the negative has to be covered1 or any other dodge used1 the time of exposure must of course be arranged accordingly4 ,as a general guide it may be stated that the details of the picture should appear brown and distinct from the ground when the print has been correctly exposed4 ,this examination of the picture must be done in a dark room1 and only one side of the printing frame should be opened1 so that the print does not shift4 ,if it is over-printed1 the picture develops badly1 the lines become broader1 the details disappear in the deep shadows1 and the ink adheres to the unexposed parts4 ,if1 on the contrary1 it is under-printed1 the ink does not adhere well to the exposed places1 and washes off in developing from the fine parts4 ,practice1 as with all manipulations1 is necessary1 and therefore one must not be disheartened by the first failure4 7,f47 ,,the ,,inking ,,up ,,and ,,developing4 ,as soon as one is satisfied that the exposure is sufficient1 the print should be taken from the frame in the dark room4 ,the next process is inking up and developing4 ,this is effected in various ways2 the ink is either spread on the dry print with a velvet roller or a thin developing ink is used with a brush1 or the bichromate is first washed out and then the ink spread on4 ,i prefer to ink up the print with a velvet roller1 on which is the developing ink1 before washing4 ,by this method ,i obtain between ink and gelatine the soluble chromium film4 ,the print develops then very quickly and well4 ,for this purpose it is laid on a glass plate1 a litho stone or any other flat surface1 a small quantity of good litho transfer ink is distributed on an inking stone with an ordinary litho roller1 and the velvet roller charged with the ink #eb from the stone by rolling it several times over the stone4 ,the print is now rolled up with the velvet roller till it appears of a general grey tone2 the details of the picture1 however1 are still visible through the ink4 ,with this first inking up1 too little rather than too much ink should be used4 ,when the inking up is finished1 the print should be laid in cold water1 care being taken that no air bells form on the surface1 and it is also advisable to frequently turn the paper over once or twice in the water4 ,after ten or fifteen minutes a change will be seen on the print1 the exposed parts will be somewhat more depressed than the unexposed1 which will have swollen to some extent in the water4 ,the print is now taken out of the water and spread out exposed side up on a sheet of glass1 very carefully avoiding folds1 and dried with blotting paper1 and the water which is on the back of the print is removed by strong pressure on the print from the front4 ,the print whilst still damp is again for a second time rolled up with the velvet roller1 by which means the details of the drawing again take the ink4 ,from the unexposed parts the ink now goes on to the roller1 in exactly the same way as in cleaning the litho stone1 and they appear covered now with a very faint tone4 ,if the first rolling up was done with too much ink1 it will be accompanied by two disadvantages4 ,firstly1 that too much ink will adhere to the details of the drawing1 and there will be the danger that in transferring the same will appear thick1 and secondly the tint will not be so well removed from the unprinted parts1 which will produce a difficult development4 ,it is therefore advantageous only to give in the second inking the printed parts the quantity of ink requisite for transfer4 ,after being inked up a second time the print is again placed for a short time in the water1 then taken out1 spread out on the sheet of glass1 and now completely developed with a pad or a tuft of cotton wool4 ,this is effected by going over all the print with light pressure and not too quickly with a circular movement1 till the drawing appears quite clear and clean on a white ground4 ,in this operation it is advisable to use as much water as possible1 in order to remove all the bichromate from the print1 which might be troublesome in the subsequent operations4 ,the washing should not therefore be stopped till the unexposed parts have lost all yellow tinge and appear nearly white4 ,if the bichromate remains in the unexposed parts1 the process continues during the drying of the print2 these places then become hardened1 and are frequently the cause of an unsatisfactory transfer4 ,one of the chief requisites is1 however1 that too much ink should not be used in inking up4 ,the developed drawing should not appear deep black1 but grey1 yet covered in all places4 ,the developing ink contains so large a quantity of grease that the least quantity is sufficient to form the combination previously described on the stone4 #ec ,the developed print is freed from all adhering water by pressure with half-damp blotting-paper1 and then fastened on to a board with drawing pins to completely dry4 ,the room where the development is carried on should be well ventilated1 and not be heated too much1 as the latter makes the work more difficult4 ,the drying ought not to be forced and should be allowed to take place spontaneously at the ordinary temperature of the room4 ,for transfer to zinc and for sending photo-lithographic prints it is advisable to bathe them in a #aj per cent4 solution of alum for about five minutes1 so that the gelatine film is hardened4 ,when the prints are to be used or to be transferred to stone immediately this treatment may be omitted without harm4 #b4 ,,various ,,other ,,photo-,,lithographic ,,papers4 ,the paper described above is a pure gelatine paper1 and although this has proved in practice to be satisfactory for all work that may arise1 still ,i will describe some other papers1 which have been also used in practice with good results1 and for those who do not care to prepare their own paper they have the advantage that they may be obtained commercially4 ,albumen was used first instead of gelatine and rendered sensitive by the addition of a chromium salt4 ,this paper had the disadvantage that it could not be kept1 and only sufficient paper and albumen solution for one day's work could be prepared4 ,a much greater disadvantage1 however1 was that in developing1 the albumen film was rubbed off with the pad1 and the paper was more or less rubbed up4 ,a tint was produced through this which transferred to the stone1 and thus gave rise to considerable troublesome and tedious retouching4 ,this is not the case1 however1 with the gelatine coating1 which is comparatively more resistant4 7,a47 ,,husnik',s ,,photo-,,lithographic ,,paper4 ,prof4 ,husnik has combined these two processes for the production of his papers1 as he gives a coating of albumen to a paper coated with gelatine1 which should be rendered sensitive with ammonium bichromate4 ,by this means is1 on the one hand1 the rubbing up of the paper prevented and damage to the image not easily possible2 on the other hand1 the development takes place very quickly1 as the albumen film dissolves and can be easily removed with the greasy ink4 ,husnik specially contends that with the use of these papers he obtains extraordinarily sharp images without any tint4 ,the sheets thus prepared will only keep1 however1 one or two days1 and this inconvenient operation has to be repeated every time before using the paper4 ,this applies also to the albumen solution1 so ,husnik has come to the conclusion that it is better and more practical to use plain gelatine paper2 but #ed when trouble1 time1 and cost are not of such great consideration1 then it is better to use the paper with the compound coating1 as it enables less experienced operators to produce good work4 ,the paper more recently produced by ,husnik is a pure gelatine paper1 which is rendered sensitive to light in-- ,ammonium bichromate #a part ,water #ae parts ,alcohol 7ordinary7 #d parts ,as much ammonia is added to the bichromate solution as will convert the reddish colour into yellow1 and the bath smells of ammonia4 ,the bathing of the paper must be done as quickly as possible1 and the sheet should only be drawn through the solution4 ,the exposure for this paper is from one to three minutes in the sun1 or from ten to thirty minutes in diffused light4 ,the inking up of the print should be done with a greasy transfer ink1 to which one-sixth part of wax has been added1 and the whole dissolved in turpentine to the consistence of oil4 ,the print is inked up with this thin ink1 and then gone over with a pad of cotton wool till it has taken an even gray tint4 ,when the turpentine has evaporated the print is laid in cold water1 and1 after about ten minutes1 developed with a soft thick pad with a continuous circular movement and quite light pressure4 ,after development all adhering water is removed from the print with damp blotting-paper1 and the transfer can be effected after from fifteen to twenty minutes4 ,husnik1 however1 did not rest1 and soon prepared a still better paper1 which is known at the present time commercially as 8,husnik's ,autotypic ,paper40 ,he produces this paper in large quantities1 the coating of the gelatine being effected by machines1 which certainly tends to ensure equality4 ,husnik found that by the use of less concentrated bichromate baths the fine lines were stronger after printing than from the nature of the negative they should be4 ,from one and the same negative there was obtained by the use of a bichromate bath of #a 3 #ajj a relief five times as broad as when a bath of #a 3 #ae was used to sensitize the paper4 ,this he ascribes to the colour of the gelatine being less1 so that more rays of light penetrated to the surface of the paper1 from which it would be again reflected1 and every point or line again reproduced1 which must obviously lead to an increase of the size of the same2 on the other hand1 with strongly chromated paper1 the rays of light would not only be absorbed by the intense yellow colour of the chromium salt1 but still more by the brown tone formed immediately after printing1 which makes a reflection impossible4 ,with autotype negatives this is specially striking1 as with weakly-chromated paper black shadows without details occur1 because here the quantity of light is distributed by reflection over the fine points1 and they will #ee therefore become thicker4 ,when using strongly-chromated papers the details in the shadows appear open1 clear1 and sharp4 ,the concentration of the bichromate bath cannot be increased at will1 because other disadvantages are produced1 especially such a firm adherence of the greasy ink to the print that it transfers badly and a part of it always remains behind4 ,the bichromate salt1 when as strong as #a 3 #ah1 dissolves the gelatine at ordinary temperatures1 and the baths1 neutralized with ammonia1 have the disadvantage that the greasy ink adheres too little to the print and will be rubbed away in developing the drawing4 ,in order to entirely obviate the reflection of the rays of light ,husnik uses an addition to the gelatine besides a #a 3 #bb acid bichromate bath1 which produces a pure yellow tone in sensitizing the papers1 is insoluble1 and completely penetrates the film of gelatine1 so that a reflection of the chemically active rays is entirely avoided4 ,this paper1 which is also darker coloured1 does not allow the light rays to pass through1 and is specially suitable for the transfer of autotypes to stone or zinc4 ,for sensitizing this paper bichromate of potassium1 sodium1 or ammonium is used1 but the sodium salt has acted the best4 ,in winter a #a to #bj bath is best2 in summer1 #a 3 #bb or #a 3 #bd4 ,the treatment of the paper1 as well as of the print1 is exactly the same as with other transfer papers4 ,the bath will keep for fourteen days4 ,caustic ammonia ought not to be used4 7,b47 ,,photo-,,lithographic ,,paper ,,by ,,adalbert ,,franz4 ,a photo-lithographic paper1 with which ,i have obtained very good results on stone as well as on zinc1 with all kinds of drawings1 is sold by ,a4 ,franz4 ,this is also a pure gelatine paper4 ,but ,franz adds to the gelatine solution manganese sulphate 7this must not be confounded with manganese borate1 siccative powder1 which makes the transfer ink dry so quickly that a transfer to the stone or zinc is impossible74 ,through the researches of ,,mm4 ,lumire the manganese salts have gained considerably in importance1 and they have been introduced into photo-mechanical processes4 ,when an addition of about #aj of manganese sulphate is made to the acid bichromate baths for sensitizing photo-lithographic papers1 the printed places assume a very much darker colour1 which is an advantage in judging the print1 in developing the finest lines1 and points are retained much more easily than on paper sensitized with the addition of ammonia4 ,this paper possesses the advantage1 which is also more important1 that the--especially in summer--unpleasant ammonia bath need not be used4 ,the paper is sensitized in a solution of-- ,potassium bichromate #dj-ej g4 ,manganese sulphate #e g4 ,water #a litre #ef ,ammonium bichromate ought not to be used4 ,the bath would then become cloudy immediately1 and both bath and paper made useless4 ,when sensitized the paper can be kept from eight to ten days without losing its good qualities4 ,with this a transfer ink is supplied in tubes1 which must be mixed with an equal volume of turpentine and benzine1 so that it becomes quite fluid4 ,the print1 when it is taken from the frame1 is fastened on a board with drawing pins1 and with a fine camel's hair brush coated with this fluid ink as evenly as possible1 and just so much that a light grey tone is formed on the print4 ,this paper must not be inked up with a roller4 ,as soon as the turpentine and benzine have evaporated the print is laid in cold water1 and after about ten minutes developed with a clean tuft of cotton wool4 ,the print does not show a strong relief2 the development takes place quickly and regularly4 ,the ink1 in spite of its being so thin1 is very greasy1 so that only a very light skin is necessary for the subsequent transfer4 ,the tint produced by a negative slightly too thin cannot be easily removed4 ,the other operations are the same as for the other photo-lithographic papers4 ,franz's photo-lithographic paper is characterized1 as already mentioned1 by giving extraordinarily sharp clean transfers1 which1 indeed1 maybe due to the use of the very thin liquid greasy ink4 ,it is1 therefore1 especially to be commended for very fine work4 7,c47 ,,albert',s ,,photo-,,lithographic ,,paper4 ,august ,albert's is also a very good photo-lithographic paper4 ,it can be obtained commercially in two qualities1 viz41 8,photo-lithographic paper0 and 8,autotypic high glaze paper40 ,this has been tested in the ,k4,k4 ,lehr- und ,versuchsanstalt fr ,photographie und ,reproductionsverfahren in ,vienna1 and has received a certificate of excellence4 ,the high glaze paper has a prepared film of several coatings2 the developed prints when dry keep the high glaze4 ,the sensitizing bath consists of-- ,water #af parts by weight ,potassium bichromate #a part by weight ,alcohol 7ordinary7 #d parts by weight and to this so much ammonia is added as will convert the reddish colour into a light yellow2 a small excess of ammonia does no harm4 ,the bichromate bath should not have a lower temperature than #ae ,r1 or else the solution cannot penetrate the film sufficiently1 which results in a defective development4 ,the duration of sensitizing is from four to eight minutes1 till the paper is quite soft and damped through4 ,it is preferable to sensitize too long rather than too short4 #eg ,the paper should be squeegeed on to plate-glass1 as already described1 and allowed to dry spontaneously4 ,the paper when stripped from the plate-glass shows a beautiful high glaze1 and can be kept fit for use for twenty-four hours4 ,when the paper is older it can still be used1 but the development is more difficult1 and it is better to avoid this for fine drawings or autotypes4 ,albert does not recommend a photometer to be used when printing this paper1 but by examination of the print to judge when this is correct4 ,the image should have a brown tone1 and be easily distinguished by the eye from the ground4 ,over-printing is disadvantageous1 as the lines and points become broader1 the prints develop badly1 the tint adheres firmly to the ground1 and the details in the deepest shadows are lost4 ,the inking and developing can be done by any of the known processes which is thought desirable4 ,the chief thing is that too much ink must not be used in the first inking up2 any intensification required may be effected with a second coating4 ,this is1 especially for fine drawings and autotypes1 very important1 whilst for coarser work also once inking is sufficient4 ,the prints are then placed in cold water1 and after sufficient washing should be developed with a soft pad or pad of wool1 with which any tint can be very easily removed from any parts which should remain white4 #c4 ,,the ,,photo-,,lithographic ,,transfer4 7,a47 ,,treatment ,,of ,,the ,,photo-,,lithographic ,,print ,,and ,,the ,,plate4 ,the transfer from the bichromated gelatine paper requires generally1 as regards treatment and choice of the material1 greater care on the part of the printer than an ordinary transfer1 and this increases in transferring fine drawings or autotypes on to stone4 ,in the first place the good quality of the stone should be looked to4 ,for ordinary or coarsely drawn subjects this is of less importance1 but for fine drawings and autotypes it is of the highest importance4 ,further1 accuracy and cleanliness are all important1 without which successful work is impossible4 ,on the other hand1 a transfer can hardly fail if it be accurately and correctly performed4 ,when the print comes from the developing bath1 and has been well washed so that every trace of bichromate is removed1 it should be freed from excess of water between blotting-paper4 ,it should then be dried in a not too warm place free from dust till the gelatine has completely set and feels absolutely dry4 ,the relief will have now again disappeared1 and the black and white places lie in the same plane4 ,it is best dried by pinning it to a board with drawing pins1 and then set up in a dry place4 ,in the meanwhile the transfer stone should be prepared1 which must be absolutely faultless4 ,just before the transfer it should be dry polished with pumice stone1 and then well dusted with a #eh cloth4 ,the slightest grain will give a spot in a fine tone4 ,obviously the stone must be well ground so that neither any spots nor lines of an earlier transfer can appear4 ,with an open drawing this can be corrected1 but not with an autotype2 in such a case the shortest way is to make a new print and a new transfer4 ,the print is first wiped over on the back with a damp cloth1 and then laid on damp blotting-paper4 ,after about five minutes the print is treated a second time with a damp cloth1 and then laid between damp blotting-paper4 ,it is not advisable to lay the print between ordinary damp blotting-paper1 as the gelatine becomes somewhat sticky1 and would attract particles from the rough paper4 ,the degree of dampness which is necessary for transfer may be judged in that the print must feel soft1 but the gelatine film ought not to be very sticky4 ,any further preparation of the print before transferring to the stone is not necessary4 ,the print is laid on the stone1 over it a dry sheet1 and then the cover1 and then drawn through the first time with light pressure4 ,in order to prove whether the transfer has taken well a corner may be lifted up4 ,all the ink which was on the print must be transferred to the stone1 and then the transfer has been completed in the correct way4 ,the print is now pulled off the stone and the transfer made ready1 like any other4 ,with this method of treatment the print will strip easily1 which is not the case if it was not well dried after the developing bath2 a much sharper and cleaner transfer will also ensue4 ,if the print was too damp a fuzzy1 broken-down transfer will be obtained1 because the gelatine1 which has become too soft1 will be broken down4 ,i will also mention that it is not advisable to treat fine drawings or autotypes with the rubbing-up pad4 ,it is better to go over the transfer with the roller1 and the tones are kept cleaner4 ,the stone is then gummed1 placed on one side1 and allowed to stand some hours before being etched4 ,for transferring to zinc plates which are to be etched or to be printed from1 the bichromated gelatine print should be bathed in a ten per cent4 solution of alum1 allowed to dry1 and then1 as previously described1 damped1 and then transferred under the same conditions as to stone4 ,it only remains to mention that the stone or zinc plate should not be too cold4 7,b47 ,,failures ,,in ,,the ,,photo-,,lithographic ,,transfers4 ,the failures or faults which are met with in photo-lithographic transfer may be caused by various things4 ,the squashing down rarely happens with photo-litho transfer1 because a good photo-lithographic paper will bear a considerable #ei amount of dampness4 ,when1 however1 it occurs it may be assumed that either too strong pressure or insufficient care in the setting of the stone is the cause4 ,much more frequently it happens that some parts of the print do not transfer at all1 or only in a defective manner4 ,the chief reason of this is that the print was insufficiently damped4 ,this frequently happens if ordinary or gravure prints are to be transferred with photo-lithographic prints4 ,if the printer encloses the impression on the ordinary transfer paper and the photo-lithographic together in the same damp sheet1 and if he estimates the degree of dampness from the gravure print1 the photo-litho paper will be insufficiently damped and a good transfer will not be obtained from the latter4 ,if1 however1 he waits till the photo-litho paper is damp enough1 the other impressions will be too damp and will squash out in transfer4 ,for such work the print on ordinary transfer paper and the photo-lithographic print should be kept separate1 so that the different dampness requisite for each can be regulated4 ,another case which frequently happens is that the print is contaminated with particles of dust or other foreign substances4 ,these may be flying about in the air or be on the stone1 the roller1 or the damping paper4 ,through this many transfers of fine drawings are rendered useless4 ,perfect cleanliness of the utensils and the use of the correct ones1 combined with a drying-room for the print absolutely free from dust1 are absolutely essential for faultless work4 ,the composition of the ink1 especially if it was too hard1 may give rise to bad transfers4 ,photo-lithographic papers1 which are prepared with very hard gelatine1 must be laid before transferring in lukewarm water4 ,by this means the hard gelatine becomes rather sticky1 and the greasy ink transfers much better4 ,even those points which in developing have taken up little ink1 and appear grey1 transfer completely to the stone and adhere firmly4 #fj ,,chapter ,,iv4 ,,photo-,,lithography ,,by ,,direct ,,printing ,,on ,,to ,,stone ,,or ,,zinc4 ,the processes of photo-lithography previously described are based upon the printing on to bichromated gelatine or albumen paper development with a greasy ink and subsequent transference of the greasy print to plate or stone4 ,a process may also be used in which the stone or plate is printed on direct4 ,there are in this various methods1 of which the principal are printing on to light-sensitive asphalt1 or an organic substance1 gelatine or albumen1 in combination with a bichromate salt4 ,the reason is the high sensitiveness1 which is possible1 of the substances used4 #a4 ,,the ,,asphalt ,,process4 7,a47 ,,the ,,light-,,sensitive ,,asphalt4 ,light-sensitive1 or so-called ,syrian1 asphalt1 which is prepared for photo-lithographic and photo-zincographic purposes1 can be obtained from various firms who deal in photographic goods1 and one has only to dissolve the same according to the prescribed directions4 ,this kind of asphalt is1 however1 not very sensitive1 and in use must be printed for some considerable time4 ,if1 therefore1 an asphalt of greater sensitiveness is desired it is not sufficient to merely dissolve ,syrian asphalt1 but it must undergo a preliminary preparation4 ,only that part of the asphalt is sensitive or useable for photo-lithographic work which does not dissolve in ether4 ,the insensitive part must1 therefore1 be separated out1 which is done by finely powdering the asphalt1 sifting it through a fine sieve1 and then treating it with ether4 ,all that is soluble in ether goes into solution2 the marc which is not soluble in ether is then dissolved in benzole and used as wanted4 7a47 ,,husnik',s ,,process4 ,professor ,husnik has improved this process in so far that he does not dissolve the asphalt powder in ether1 as1 according to his view1 a complete solution of all the insensitive portion is not attained by this process1 but he dissolves coarse asphalt powder completely in rectified spirit of turpentine to the consistence of a moderately-thick syrupy mass1 until no hard particles or a residue are contained in the solution4 ,to this viscous asphalt solution a plentiful quantity of ether is added gradually1 and with constant stirring1 and a big flask should be used for this purpose4 ,after a sufficient quantity of ether has been added a pitch-like deposit #fa separates out at the bottom4 ,in order to test whether there is still any light-sensitive asphalt in the supernatant liquor a small quantity is poured into a glass and mixed with ether1 when if a precipitate ensues more ether must be added to the big flask4 ,after standing for about twenty-four hours the ether contains all soluble insensitive constituents of the asphalt2 the pitch-like residue in the flask1 after pouring off the solution1 is again treated with ether1 so that all turpentine is extracted and any stray insensitive particles are dissolved4 ,the pitchy residue is now removed from the flask and allowed to stand in a porcelain dish in a warm place1 with frequent stirring1 till it is quite freed from ether1 and has formed a hard1 brittle1 black shining substance1 which can be easily broken up into powder with the hand4 ,this product is now the light-sensitive asphalt1 which is dissolved for use in anhydrous benzole4 ,as benzole is only to be obtained anhydrous with difficulty1 some chloroform is added to the solution in order to prevent the running together in drying1 whence the film would become unequal and patchy4 ,the coating of the stone or plate with the asphalt film is very simple2 it should be placed horizontal1 and then whirled rapidly on a whirler4 ,printing under a clear negative takes from a quarter to half an hour in direct sunlight4 ,the picture is developed with turpentine4 7b47 ,,valenta',s ,,process4 ,valenta recommends for photo-lithography asphalt which has been sulphurized by the wet process1 as it possesses a considerably higher light-sensitiveness than that which is not sulphurized4#c #c ,eder's 8,jahrbuch der ,photographie10 #ahib1 p4 #bda4 ,the process is as follows3--#ajj g4 of raw ,syrian asphalt are boiled in a retort with an equal quantity of raw pseudo-cumene1 which has the formula ,c#f;,h#c7;,,ch#c7c1 and a boiling-point of about #agj ,c41 with #ab g4 of flowers of sulphur1 which should have been previously dissolved in the pseudo-cumene4 ,when after about three or four hours' boiling the evolution of sulphuretted hydrogen has ceased1 the pseudo-cumene is distilled off and the black pitchy residue dissolved in benzole in the proportion of #d 3 #ajj1 and used for the preparation of the plate or stone4 ,the sulphurized asphalt prepared in this way is almost insoluble in ether1 but dissolves fairly readily in benzole1 toluene1 xylene1 cumene1 and turpentine1 and is very sensitive to light4 ,with this asphalt good prints are obtained even in bad1 cloudy weather4 ,for use four parts of the sulphurized asphalt are dissolved in #ajj parts of benzole1 the solution filtered and diluted till a thin film on a zinc plate shows a golden yellow colour4 ,exposure of the asphalt solution in an open flask for from half to one hour in sunlight is advisable4 ,for developing the asphalt image rectified oil of turpentine free #fb from acid is used2 the best is ,french or ,austrian4 ,the development may be accelerated by adding ,hungarian or ,russian turpentine1 which1 however1 attack the asphalt image2 it can be restrained by the addition of ligroin1 benzine1 or wood oil to the turpentine4 ,zinc plates are best developed in a dish1 stones by making a wax margin round the drawing4 ,the oil of turpentine is poured on and rocked to and fro4 ,rubbing with a pad of cotton wool1 etc41 should be avoided4 ,after development the plate should be well washed under a stream of water1 and before gumming1 the plates should be exposed for some time to light1 as this makes the ground more resistant to the etching4 7,b47 ,,coating ,,the ,,stones4 ,the stone or zinc plate is now coated with one of the above-described asphalt solutions1 or with the following3-- ,asphalt #bj g4 ,chloroform #cjj g4 ,benzole #ajj g4 ,oil of ,lavender #bj drops4 ,the solution must be thin1 so that it flows over the stone well and does not form unequally-covered patches4 ,the subsequent manipulations must be conducted in the dark4 ,the stone which is to be used must be well ground1 and polished with dry pumice stone1 well dusted1 and be absolutely flat4 ,it ought not to have any depressions1 as the negative would not lie in contact there4 ,the places would not print sharp1 and therefore a bad result would be obtained4 ,the necessary quantity of the solution is now poured into the middle of a well-polished stone1 and distributed as evenly as possible by rocking backwards and forwards4 ,when thoroughly distributed the stone should be placed on the whirler and kept for some time in motion4 ,the asphalt solution must be as thin as possible1 so that it appears yellowish-brown and the colour of the stone appears through it4 ,if the stone is only covered all over the film can be very thin2 on the other hand1 if it is too thick it will not print through1 and will develop badly1 as too much of the asphalt will dissolve4 ,if zinc plates are used for printing they should be prepared as previously described on p4 #f4 ,zinc plates for deep etching must be well ground and well polished1 and ought not to repel water4 ,the zinc plates are coated the same as the stone4 7,c47 ,,printing4 ,when the film is absolutely dry1 which will be in about fifteen minutes1 printing may be proceeded with4 ,for this purpose the negative is either laid on to the asphalted stone1 film side down1 and pressed down with screw bands1 or it is laid1 the glass downwards1 in a specially-constructed and very strongly-built printing frame1 which is provided with a sheet of plate glass1 and the #fc asphalted side of the stone laid on this1 the printing frame closed1 and then exposed to light4 ,the exposure continues according to the strength of the light and the nature of the negative from #ae minutes to #a hours4 ,if the film of asphalt be thin and the negative clear it may be printed to #ah or #bj degrees in ,vogel's photometer4 ,this kind of printing always requires some experience1 as various factors1 such as the thickness of the asphalt film1 the density of the negative1 also the fineness of the drawing1 have to be taken into account4 ,it will be understood that the asphalt film must always be coated as evenly as possible4 ,if it is printed too long the stone will not develop at all1 or only in parts2 if it is printed too little the drawing wholly or partially dissolves4 ,in both cases an unsatisfactory result will be obtained4 ,negatives very clear in the lines of the drawing1 and well covered in the ground1 are here more essential for success than with the chrome gelatine process4 7,d47 ,,developing ,,and ,,inking ,,up4 ,when properly printed the frame and the stone should be brought into the dark room and development proceeded with4 ,for ordinary ,syrian asphalt rectified turpentine can be used1 and one of two methods may be adopted4 ,the stone is laid in a pan as straight as possible1 and then flowed over with turpentine1 which should be allowed to remain on it for some time1 and then poured off into the pan4 ,fresh turpentine is now applied till the drawing appears clear and distinct4 ,the turpentine which is allowed to run off can be used for washing purposes4 ,an edging of warm gutta-percha may also be made round the drawing1 and then turpentine poured on to it and the stone rocked up and down till the drawing is developed4 ,the very sensitive kinds of asphalt of ,husnik and ,valenta are much more readily soluble than the ordinary ,syrian asphalt4 ,in developing one must go carefully to work1 and not allow the turpentine to stay on the stone a long time1 but to pour it over the stone1 which should be inclined so that it can run off4 ,this can be repeated if required4 ,it can be well and safely developed if half and half of turpentine and linseed oil is used1 which1 however1 has the disadvantage that the stone becomes greasy1 but this can be taken off by the expert printer4 ,after developing the stone should be well washed under a strong stream of water1 then allowed to dry in the light1 as by this the asphalt film becomes more capable of standing the etching1 and then be coated with neutral or very slightly acidulated gum4 ,after gumming1 the stone is again dried and allowed to stand for some hours to rest1 after which it can be inked up and etched1 and finally sharp etched4 ,the zinc plate is1 after development1 also well washed1 then allowed to dry1 treated with thin gum solution1 then with an #fd etching solution of tincture of galls or gallic acid and phosphoric acid1 and inked up4 ,prints on zinc plates for deep etching are gummed after developing1 and if the asphalt film is perfect without rubbing up with a pad1 which thickens the drawing1 etched for some minutes in very dilute nitric acid4 ,many lithographers are accustomed1 and indeed it is necessary with some transfers1 to rub the prints up with greasy ink4 ,the process is as follows3--,greasy transfer ink is diluted with some turpentine1 and after the stone has been gummed and allowed to dry1 then washed1 the drawing is wiped over with a soft pad with this dilute ink1 when the ink adheres to the drawing1 strengthens it1 and if great care is not taken1 thickens it also4 ,with asphalt prints this is absolutely useless1 and for other direct prints1 as well also as for good chromated gelatine prints1 in most cases unnecessary4 ,the exposed asphalt combines so intimately with the stone that strengthening with a greasy ink is quite unnecessary1 is indeed absolutely purposeless1 as the ink can neither penetrate the hard asphalt film nor combine with it4 ,the film of asphalt alone is so resistant to every etching solution that it is for this reason absolutely useless to strengthen it4 #b4 ,,other ,,processes4 ,besides the asphalt other mixtures of other light-sensitive substances may be used for direct printing1 and these are mostly organic substances in combination with a chromium salt1 and possess also a greater sensitiveness to light than asphalt4 ,the solutions which have been specially used in our establishment consist of-- 7,a74 ,albumen #e g4 ,ammonium bichromate #c g4 ,distilled water #ejj g4 ,ammonia #ae-bj drops 7,b74 ,chloroform #bej g4 ,benzine #ej g4 ,alcohol #bj g4 ,mastic #b g4 ,aniline red #b g4 ,solution ,a is strongly sensitive to light1 and is used for coating the stone or zinc plate2 with solution ,b the stone is coated before developing4 ,the details of the process are as follows3-- 7,a47 ,,coating ,,the ,,plates4 ,after the stone has been carefully polished and well dusted it should be first flowed over with distilled water1 in order to increase the possibility of spreading the sensitive solution4 ,when the water has run off1 the stone whilst still damp should be flowed over with solution ,a1 and care should be taken that the same is evenly distributed and that no bubbles form4 ,the stone should be #fe placed immediately on the whirler and rotated till the solution is dry4 ,obviously a thick film must be avoided1 as in such a case the print would not adhere to the stone4 ,if a zinc plate be used it must be well prepared and be rendered free from grease4 ,to prove this the plate is flowed over with distilled water1 and when this spreads equally all over and is not repelled from any part1 the solution can be poured on4 ,if1 however1 the plate does not willingly take water everywhere1 it must be again cleaned or polished4 ,the other operations are the same as for the stone4 7,b47 ,,the ,,printing4 ,when the film is quite dry1 printing may be proceeded with4 ,the duration of printing depends obviously also here again on two important factors--the quality of the negative and the strength of the light4 ,under a good negative with absolute bare glass in the lines of the drawing ,i print to about #aj ,vogel1 for example3-- ,in direct sunlight 7middle of ,april1 #aa a4m47 #b min4 ,in the shade 7middle of ,april1 #aa a4m47 #e min4 ,in electric arc light 7#cjjj c4p41 at a distance of #ej cm4 #bj ins4 without reflector7 #be min4 ,the picture is faintly visible4 ,if the negative was too thin1 or if it be over-printed1 the image develops badly or not at all4 ,with under-printing the film washes right away4 ,immediately after printing the stone or plate is coated with solution ,b1 which is distributed as evenly as possible by rocking backwards and forwards4 ,it is not necessary1 however1 to obtain even distribution with a whirler4 ,the whole of the coated surface becomes deep violet4 7,c47 ,,the ,,development4 ,when solution ,b has become completely dry1 the stone is placed in a suitable vessel with pure water4 ,after about five minutes the places not affected by light dissolve if the stone is rocked1 and it is only necessary to go over the drawing with a pad of cotton wool to clean the same completely4 ,the drawing now appears a deep violet on a bright ground4 ,the development is continued without rubbing strongly with the pad--which might rub up the drawing--till all the details of the drawing appear clear and distinct4 ,this especially applies to the details in the deep shadows4 7,d47 ,,further ,,manipulations4 ,when the stone or plate is correctly developed1 which can be easily told1 it should be well rinsed and again exposed to make the film adhere firmly4 ,it should then be gummed and treated as previously described in the asphalt process4 ,the 8rubbing up0 of the stone or plate is not necessary2 it is better to roll up the drawing with an ink roller4 ,zinc plates for deep etching can be lightly etched1 then dusted with fine asphalt of resin powder1 heated and then further etched4 #ff ,r4 ,j4 ,sachers1 of ,toronto1 ,canada1 published a sensitive solution which has the following composition3-- ,distilled water #aej parts ,fish glue #ej parts ,ammonium bichromate #b parts ,ammonia #b parts ,chromic acid #a part ,this solution is brown1 not very transparent1 with an olive green tinge1 and must stand and settle at least twelve hours before it can be decanted1 filtered1 and used4 ,the time of exposure is about-- ,direct sunlight #b-e minutes ,diffused light #ab-ae minutes ,electric arc light 7#cjjj c4p41 #ej cm47 #cj minutes ,the image appears a bright brown on the golden yellow ground of the plate4 ,the development is effected in an aqueous solution of methyl violet1 when the image assumes a beautiful blue violet colour4 ,the developed image is hardened with alcohol4 ,the results by this method are very good1 and although this is recommended for half-tone etching1 it is also suitable for photo-lithography4 ,excellent results also attend the sensitive 8,marine glue solution10 prepared by ,a4 ,hebensperger1 of ,munich1 to which a second solution called 8,chlorogutt-losung0 is added4 ,the sensitiveness to light is very high1 and the treatment about the same as with the first described substance4 ,the 8marine glue solution0 consists of albumen1 bichromate of soda and ammonia4 ,the dye solution of ,victoria blue dissolved in benzine4 ,the process published by ,waterhouse consists of coating a prepared zinc plate with a thin chromated solution1 and then drying in a few minutes with a gentle heat-- 7,a47 ,arrowroot #b parts ,potassium bichromate #i parts ,water #gjj parts 7,b47 ,alum #a part ,water #a part ,for use mix-- ,solution ,a #dj parts ,potassium bichromate #e parts ,solution ,b #ae parts ,this is printed under a reversed negative for about six minutes in the sun4 ,the plate is then laid for about half an hour in cold water in order to remove the chromium salts1 and then cleansed from all soluble parts with a pad1 and after well washing set up to dry4 ,it is then inked up with transfer ink1 and after about fifteen minutes washed with turpentine4 ,this process1 as1 indeed1 all direct printing processes1 offers many advantages for preparing colour plates from a coloured object with one negative4 ,the register of the separate plates is very exact1 which is not always the case with a transfer process4 ,in reproducing line drawings the unnecessary parts on the stone or plate can be covered4 #fg ,,chapter ,v4 ,,the ,,half-,,tone ,,process ,,for ,,photo-,,lithography4 ,the half-tone process is used in photo-lithography to reproduce originals which do not contain distinct lines or points1 but closed tones1 which are executed either in one or several colours4 ,with this process any coloured picture1 oil1 water1 pastel1 indian-ink or sepia drawing1 as well as any photographs from nature of living1 moving scenes1 or still life objects can be prepared for reproduction on the printing press4 ,i will first describe briefly the theory of the process1 and then come to the practical part4 ,as regards the photographic part and the quality of the negatives1 in the present state of this method of reproduction the same principles apply as in line reproduction2 where they differ ,i will mention the same4 ,the duration of printing1 the transfer of the image to the stone1 as well as the other arrangements will be described in the different processes4 ,we divide this chapter again into two sections3 #a4 ,methods in which the half-tone is broken up when making the negative4 #b4 ,those methods in which the formation of the grain is effected after the negative has been made by some suitable means4 #a4 ,,breaking ,,up ,,the ,,half-,,tone ,,on ,,the ,,negative 7,,autotypy74 ,of the various methods by which a breaking-up of the half-tones can be obtained1 the so-called 8autotypy0 is the one most used practically4 ,with this process the half-tones are broken up in the negative4 ,as every important technical discovery is formed not at once1 but must be made by a longer or shorter series of smaller discoveries or improvements in order to attain the hoped-for goal1 so was it also with autotypy4 ,from the work of ,paul ,pretsch1 ,mariot1 ,brown1 and ,fred4 ,e4 ,ives the present state of the certain and beautifully-working half-tone process gradually evolved1 and the last process1 which ought to be considered as the immediate predecessor1 is far outshone by autotypy as now practised4 ,early attempts were made to obtain a printable image on stone by breaking up the chromated gelatine film1 so that an irregular so-called serpentine grain was formed on it1 which corresponded #fh fairly well with the theory of lithography1 but gave no precise lines and no beautiful gradations of stone4 ,if the grain was somewhat too coarse the effect of the picture was lost1 the tone gradations were too far apart1 and only light and shadows were given2 if the grain was too fine the stone was not printable4 ,a further experiment was printing a design over the original1 the strength of which had to be brought in correct proportion to the original2 the impressing of a design was also tried1 and when using this method the correct angle of the incident light when making the exposure had to be taken into account4 ,further experiments1 which were principally carried out by ,mariot1 ,cronenberg1 and others1 were founded principally on the basis of breaking up the tones in printing4 ,for this a lineature or screen on glass1 or a gelatine film1 was introduced between the negative and the sensitive film4 ,others1 again1 coated the blank glass plate with a lineature1 and prepared the plate afterwards with collodion or gelatine emulsion for the exposure4 ,it will be thus seen how this method of reproduction developed step by step till net-work of silk muslin or woven horsehair1 and finally grating images1 strongly reduced by photography1 were placed in front of the photographic plate4 ,thus were efforts made to make half-tone pictures suitable for printing by litho- or typography1 and although the end was very nearly attained1 yet the crux was not quite solved4 ,these methods did not1 however1 yield the desired result1 namely1 a beautiful sharp clear image4 ,there was still required a considerable improvement of the existing methods1 and this was made by ,meisenbach1 of ,munich4 ,the principle by which ,meisenbach prepared his images was essentially different from the previously-described results4 ,he broke up the half-tones1 also by means of a lineature1 into a printable grain1 but the process was essentially different from the previous methods1 in that ,meisenbach used a glass plate on which1 on a black ground1 a grating was drawn till the glass was laid bare1 and in this way prepared a lineature which consisted of clear glass1 transparent lines and absolutely opaque lines4 ,he produced1 first1 an ordinary negative1 from this a positive1 and from this1 by the interposition of the lineature1 the actual half-tone negative for making the printing plate4 ,the lineature or screen was in the second exposure interposed before the sensitive plate1 and half the time of exposure given2 then the screen was turned till the line first obtained crossed the second at an angle of #ij1 and then the exposure was completed4 ,by this means an absolutely certain breaking up of the half-tones into mathematically exact points was attained1 and the most important step made in making photography useful for preparing printing plates for the two principal methods1 typographic and lithographic4 ,meisenbach has called his process 8autotypy40 ,it was1 indeed1 #fi somewhat inconvenient1 but had the advantage that on the negative and also on the positive any retouching that was necessary could be done4 ,i cannot here enter into the numerous simplifications and improvements of ,meisenbach's process which1 as well in the photographic process as also in the preparation of the lineature1 were in the course of time made partly by him and partly by ,carl ,angerer1 ,gillot1 ,bussod and ,valadon1 ,lefmann1 and others1 since1 on the one hand1 it would carry us too far1 and1 on the other hand1 they may be considered as a natural consequence of the discovery4 ,i will only mention that it was found after a short time that the two exposures and the production of the necessary positive could be omitted1 and that the lineature could be simply interposed before the sensitive plate in the first exposure1 by which an important simplification of the work was attained1 and1 thanks to the continued perfecting of the processes1 no detraction of the good results was thus produced4 ,i do not consider it superfluous to give a short explanation of the action of the interposed lineature on the photographic plate during exposure4 ,if we take1 for the sake of simplicity1 not a picture1 but a scale with four or five-tone gradations from light to deep black1 the light tones will act more or less on the sensitive photographic plate according to their degree of brightness1 but as the rays of light have to pass through the cross-lined screen interposed between the lens and sensitive plate1 and as the rays can only pass through the transparent parts and not through the opaque1 no homogeneous surface is obtained on the negative1 but a tone produced by the cross-lines of the screen4 ,if the tone was very bright1 the rays reflected with great intensity on the sensitive plate will completely decompose the silver film4 ,since they are prevented by the screen from acting with equal power on all places of the surface1 these places will show very plainly on the negative1 and the result is therefore a darker tone on the same1 which is marked with bright fine lines1 corresponding in thickness to the screen plate4 ,if the original tone was darker so many rays of light will not be reflected1 and these have thus not the power to impress the screen on the sensitive plate in full intensity2 the result is therefore on the negative a tone which does not contain such strong dark lines as the first2 the tone appears lighter in the negative1 and in the print from the same darker than the first4 ,in the reproduction of deep black surfaces finally no rays of light are reflected1 therefore no rays of light can penetrate through the screen1 and because actually here no chemical change of the light sensitive film takes place1 we obtain a negative which is clear and transparent in these places1 that is to say without any interruption1 which gives in the print a full black tone4 #gj ,in this process there comes1 however1 to our aid a very important physical law1 namely1 the diffraction of light4 ,a ray of light passing through a round hole or a slit and falling on to a black surface is represented not the same size as the slit1 but more or less broadened the more the receiving surface is moved away1 and in the middle the brightest light will be1 and this gradually fades off into shadow towards the margin4 ,if we take now the opposite1 and use instead of the hole or slit a black surface or a conglomerate of such in the form of points1 squares1 or other geometrical figures1 and if these be placed before a screen illuminated with a bright light1 these figures become somewhat smaller with this bright illumination1 whilst with a weaker illumination they are represented in correct strength4 ,where the light acts in its full intensity1 or in excess1 in a manner of speaking it is diffracted or bent over the figures1 and proportionately makes them smaller4 ,this law does good service in autotypic work4 ,as we have seen1 the rays of light must pass through the screen during exposure4 ,this screen consists of equally thick opaque black and transparent white lines4 ,where the light acts with full intensity it will be more diffracted over the black lines4 ,it makes the lines of the screen broader on the negative1 and will1 therefore1 have more covered places1 which in the after printing of the prints cannot be penetrated by the light1 and thus represent the light places in the print covered with fine dots4 ,the darker the tone the less the rays of light reflected1 and the less1 therefore1 can the light be diffracted4 ,as the tones get darker the lines of the screen become of equal value on the negative1 till finally1 when at the opposite end of the screen1 they totally disappear in the deep blacks4 ,a valuable quality of a correctly-prepared autotype is1 therefore1 that the covered lines or the covered grain appear of different strengths on the negative4 ,in the high lights they are stronger1 in the half-tones weaker1 till finally in the black parts they have totally disappeared4 ,a further not less valuable property is that the grain in the highest lights is not sharply defined1 does not appear as a square point1 but is rounded by the diffraction of light1 which gives a softer1 more beautiful appearance and plasticity4 ,whilst the light reflected from the brightest parts of the drawing acts with full intensity1 and is diffracted over the figures standing in its path and makes the same smaller1 and cuts off the sharp corners and gives more covered surfaces to the negative1 as it decreases according to the more or less deep shadows of the drawing1 and can only act now with less intensity through the open places of the screen1 the result is that the points become larger1 till finally in the deepest parts it is quite inactive1 and the shadows begin to block4 ,the action of the light rays of different #ga strengths reflected on to the negative in accordance with the brighter and darker tones of the drawing1 taking into consideration the print1 can be graphically represented as a pyramid of which the base represents the deepest shadows and the point the high lights4 ,if we interpose a cross-lined screen1 or more correctly called a grain plate1 before the sensitive plate1 we obtain1 graphically considered1 grain figures1 actually of many more very different sizes1 as shown in ,fig4 #g1 #a-f1 in which the smallest points represent the high lights of the drawing1 and those becoming gradually bigger the gradually increasing shadows4 ,illustration3 ,fig4 #g4 ,the original grain plate contained1 measured diagonally1 five black points1 five white interstices to the millimetre4 ,the figures represent enlargements of a negative made with the above-named grain plate1 and for this the grain plate was one millimetre distant from the sensitive plate4 ,the accompanying ,figure #h1 #a-f1 represents very much enlarged the scheme of grain of an autotype from a perfectly-executed wash drawing1 with a screen of five opaque and five transparent lines to the millimetre1 in equal proportions of black and white1 at a distance of one millimetre from the sensitive plate1 with equal time of exposure before and after the turning of the screen1 and obviously with correct exposure for the whole4 ,the scheme is only given here in six gradations of tone4 ,as a matter of fact1 a good autotype has at least from six to eight times the number of tones1 as with a sharp screen and an original cleanly #gb and sharply drawn in many tones1 the light reflects the least alteration of tone in the size of the grain4 ,illustration3 ,fig4 #h4 ,as previously mentioned1 the smallest points represent the highest lights of the drawing2 the larger1 according to our graphic representation1 the darker tones1 but a correct reproduction of the grain4 ,in a similar way obviously the formation of the lines on the negative behave with an interposed but not revolved screen4 ,here also the lines in the high lights of the negative appear more covered than in the shadows4 ,the proportion of grain can1 if the original requires it1 be so far altered by not giving equal exposures for each position of the screen--for instance1 in the proportion of two to one or three to one4 ,we obtain then on the given scheme less closed tone gradations1 #c1 #d1 and #e1 and just before #c1 and between and after #e1 tone gradations1 no single black and white points1 but more or less jagged black or white lines1 whilst the open black grain in #a and #b becomes more an oval instead of the round form in #f1 and beyond the round openings are drawn out into ovals4 ,we have1 however1 in autotypy still the physical law1 which is very useful to us1 and that is the greater or less distance of the point from the light surface4 ,the nearer a point or a figure is brought to the wall on which it should throw the shadow1 the greater the size of the original1 and so much sharper will be the outlines of the shadows4 ,the more the point or the figure is #gc removed from the wall the less the shadow will correspond to the shape of the original2 it will be smaller and less defined4 ,the shape will also frequently change1 and a square will become a round4 ,we have then in the near or distant position of the lineature to the sensitive plate1 on which it throws its shadow1 an important assistance to act on the general tone gradations of the image4 ,let us remember that in focussing the shadow-forming object on to the surface on which the light falls1 we obtain the same formed in all its actuality on the receiving surface2 therefore1 when this refers to a lineature with equal proportions of black and white1 we obtain these in equal ratio4 ,when1 however1 we remove the lineature from the light-receiving surface1 the shadows which it throws contract1 the lights predominate1 we obtain no longer the ratio of #a 3 #a between light and shadow1 but about #ae 3 #a and so on4 ,by placing the lineature close to the sensitive plate1 we obtain more closed tones1 and as this gradation of tone is carried naturally throughout the whole of the image1 also less high lights1 less deep1 middle shadows1 whilst the deep shadows appear in their natural strength4 ,with the removal of the lineature from the sensitive plate1 on the other hand1 the ratio of tones for the whole image1 as well as for the details1 is displaced4 ,in the first place we shall obtain a picture which contains more contrasts of black and white4 ,the light tones become considerably lighter by the reduction of the shadows4 ,the dark parts1 on the other hand1 attain full vigour4 ,in the first place1 therefore1 the original has to be considered as regards the distance of the lineature from the sensitive plate4 ,obviously1 therefore1 no accurate directions can be given in a case where feeling and experience are required4 ,next to the original1 the number of the lines on the screen has to be considered4 ,as a rule1 one uses lineatures with five or six transparent and opaque lines to the millimetre 7 #abe-aej to the inch71 and for these a distance of to #a mm4 7 #a_/ej-a_/beth inch7 from the sensitive plate is generally sufficient for most cases4 ,with a less number of lines the distance can be increased4 ,autotypy is a process in which unprintable half-tones can be broken up by the use of a well-defined physical law into a mathematically determined grain1 and the size of the grain can also be regulated to a certain extent with certain precautions4 ,it is1 therefore1 easily understood that the autotypic process is now very general and most used1 and not only in the limited department of photo-lithography1 but in a more extended way1 does excellent service for the preparation of illustrations of all kinds1 for the simplest picture for the daily paper as for the finely-printed magazines and journals1 for simple monochromatic printing1 and for the highest colour printing4 ,with accurate knowledge and command of the technique of #gd photography and lithography1 there is required before everything1 for successful work1 a faultless screen plate4 ,the indispensable requirements which must be found in the screen are absolutely opaque black lines and bare glass in the white lines4 ,the home preparation of such a screen plate is a somewhat difficult matter1 and will not be absolutely successful if one has not a faultless ruling machine1 a composition which is thoroughly opaque1 which adheres well to the glass and gives clean1 sharp lines in ruling1 and which does not chip1 and it will require a tremendous expenditure of patience and perseverance4 ,glass screens of excellent quality may now be obtained commercially4 ,for reproduction of the very highest quality1 a drawn and etched screen plate is more suitable than one merely ruled on pigment1 which never gives such sharp results4 ,from various firms etched screen plates may now be obtained either as single or crossed-line screens1 which fulfil all requirements4 ,the best screen to use is one with five or six opaque and transparent lines to the millimetre1 which corresponds with #b1ejj to #c1fjj points to the square centimetre4 ,the above number of lines will suffice for nearly all work1 and such screens give reproductions in which the grain is no longer visible to the naked eye1 but appears as a closed tone4 ,it is not advisable to go beyond this number of lines1 except in special cases1 when the details of the drawing in the original are specially small4 ,with a smaller number of about three or four lines to the millimetre1 too coarse a grain results1 of which the individual points become too plainly visible1 and these are distracting and act roughly1 and do not accurately reproduce the gradation of tone4 ,the best proportion between opacity and transparency is #a 3 #a4 ,from this is obtained1 according to my opinion1 the most beautiful and restful tones4 ,it must also be remembered that the opaque spots actually lose considerably in strength in the brighter portions of the picture by the spreading action of the light4 ,the printing may be done on bichromated gelatine paper1 with which1 however1 extremely accurate inking up of the print is essential1 and the prints must not have too much ink and must be very carefully printed4 ,if1 however1 very good1 clear negatives are used1 either of the direct printing methods1 as already described in ,chapter ,,iv41 is to be preferred4 7,see ,no4 #d ,supplement47 #b4 ,,photo-,,lithographic ,,processes ,,in ,,which ,,the ,,grain ,,is ,,not ,,formed ,,during ,,the ,,exposure4 ,of the many existing processes by which the breaking-up of the half-tones into printable lines or grain is effected1 not in the negative1 but subsequently by mechanical and chemical action on the stone or plate or the transfer film1 ,i will only mention those #ge which appear to me to be the most important1 the new methods which have already found firm footing in practical work or which appear likely to do so4 ,all the older processes1 which were either never actually successful or have been superseded on account of difficulty of working1 we may properly pass over4 7,a47 ,,the ,,patent ,,asphalt ,,process ,,of ,,orell1 ,f,,ssli1 ,,and ,,co4 ,,used ,,for ,,the ,,preparation ,,of ,,colour ,,prints4 ,i have already mentioned that the use of light sensitive asphalt for the preparation of printing plates for the various branches is by no means new4 ,the fundamental principles of the well-known processes we find also used in the process of ,orell1 ,fssli1 and ,co4 ,the grained stone is coated with a thin film of light-sensitive asphalt1 the composition of which we have previously learnt1 and exposed under a reversed or stripped negative4 ,the image after correct exposure is developed1 and then1 according to the construction of the asphalt1 in combination with the graining of the stone and the developer1 there is formed a finer or coarser grain1 or a closed or open image4 ,the development is effected with petroleum1 to which one-fifth or one-sixth of its volume of benzine is added1 or with turpentine alone4 ,development takes place rather rapidly1 and after a short time the image appears on the stone4 ,the print is then treated as was suggested in asphalt printing2 the stone is first gummed1 and then by rolling up with ink and etching rendered suitable for printing4 ,the pictures produced by this have a very fine grain and are in appearance very much like good collotypes2 still two or more tones are necessary to obtain an absolutely closed and vigorous action4 ,very similar to ,orel and ,fssli's process is the following1 also patented4 7,b47 ,,the ,,colour ,,printing ,,process ,,of ,,wezel ,,and ,,naumann ,,of ,,reudnitz1 ,,leipzig4 ,in this process also all the colour stones of a chromo picture are produced from a single stripped and reversed negative which is taken of the original4 ,for the preparation of any colour stone there are three distinct stages4 ,the first stage is the exposure1 the second the development1 and the third the development continued still further1 and any necessary small help by the lithographer4 ,in each stage a special mode of treatment is required1 according to whether the stone in question is to be used for a light1 a more vigorous1 or full colour4 ,the stones for grey and the light blue or light red inks--thus those for many surfaces1 but with few details--are treated differently to those for yellow1 the second red #gf or blue2 and these1 again1 differently to those for brown or quite dark colours4 ,everyone only slightly conversant with colour printing knows that the first plates are used for the general tones of the picture1 and contain1 therefore1 few details1 and with the exception of the highest lights are tolerably full2 the latter plates1 on the other hand1 which are devoted to the darker colours1 contain less toned surfaces1 but1 on the contrary1 more details of the drawings4 ,in order to attain this correctly the three stages of the production of the plates are carried out with this end in view4 ,it should still be mentioned that the more or less fine graining of the stone determines the general ratio of the grain of the picture4 ,the first stage is the exposure of grained stone coated with asphalt4 ,with longer or shorter exposure it is possible to make the asphalt film more or less soluble1 that is to say1 to make the same more or less capable of resisting ethereal oils4 ,it is therefore possible at this stage1 by long exposure of the asphalt film1 to give to the colour stone for bright colours more tone and less details4 ,the stones for the darker inks are printed for a shorter time1 and the asphalt film is less capable of withstanding the solvents1 and the resulting plate contains less tones and more details4 ,finally1 the plates for the deep colours are normally printed2 the asphalt film is still less resistant1 and consequently the stone will only have tone and details on those places which in printing ought to be the darkest4 ,it is possible1 therefore1 by correct manipulation of this operation1 to obtain approximately the correct colour plate4 ,there is1 however1 in the second process a corrector for the first4 ,the development may be so performed that by the longer or shorter use of strong solvents1 ,hungarian or ,russian turpentine1 more or less of the asphalt will be dissolved4 ,thus if a slight error is made in printing it can be made good in developing4 ,as a rule1 the stones for bright colours1 which consist of many tones1 are not developed so long as those for the stronger colours4 ,the actual stones for the deep colours are very strongly developed1 so that almost all the delicate parts of the picture disappear1 and only the dense strong parts remain on the stone4 ,still the fine details which are to be found in the vigorous parts1 and which cannot be recognized1 must be brought out4 ,the fine parts of the drawing must be quite clear if the details are to be recognized1 or the picture will be a fuzzy copy of the original1 wanting in structure4 ,this fault is remedied in the third stage of the treatment1 in which a strong development of the picture is effected with strong acting oils or benzole and turpentine4 ,as this operation1 however1 would also wash away such delicate places which ought to remain on the colour stone1 they must be covered with solution of gum and allowed to dry4 ,then those parts not covered with gum1 #gg in which the details of the image cannot be seen1 are painted for a longer or shorter time1 as may be required1 with a brush dipped in the developing solution1 and when correctly developed may be covered up4 ,the lighter places are treated for a shorter time1 the very dark places for a longer time4 ,by this treatment the particular parts of the picture become lighter and lighter1 the details appear more and more2 and1 finally1 the whole picture shows as it should do4 ,then the gum is washed off and the stone subjected to the already described treatment1 so as to make it suitable for printing in quantities4 ,finally1 the lithographer can make corrections with a needle or tusch4 ,this process may be used1 therefore1 to prepare colour-printing plates from a negative obtained in the camera from an oil painting or any coloured original4 ,the negative for this process must contain all the details very clear1 must be soft1 and not be too dense4 ,the different colour plates are thus in this process obtained by long or short printing1 by strong or weak developing1 and finally the details in the dark plates are obtained by separate development and covering up the other places with gum4 ,the breaking up of the half-tones into printable grain is effected by graining the stone1 before coating with the light sensitive asphalt film4 ,on the finer or coarser graining of the stone depends also the structure of the grain of the image4 ,this process yields the most beautiful results with correct manipulation1 and in the hands of an expert photographer and lithographer is a valuable aid to the preparation of colour plates4 ,the process is patented4 7,c47 ,j4 ,,bart,s' ,,process ,,for ,,preparing ,,photo-,,lithographs ,,and ,,phototypes ,,in ,,grain ,,and ,,half-,,tone4 ,barts' process belongs to those in which the breaking up of the half-tones into a printable grain is effected subsequently on the plate or stone by mechanical means4 ,this is attained in a very original manner by means of a sandblast1 which makes the half-tone printable4 ,we have here not the breaking up of the half-tones in a mathematically regular manner1 dependent on optical laws1 as is the case with autotypy1 but a method similar to that of ,pretsch1 which obtains the printable grain by reticulation of the chromated gelatine film1 or other discoverers who attain the same result by asphalt dusting or some other means4 ,for this process a well-polished litho stone or zinc plate is coated with a thin film of varnish1 composed of-- ,chloroform #cjj g4 ,mastic #e g4 ,asphalt #aj g4 ,benzole #cjj g4 ,linseed oil #b g4 #gh ,on the stone or plate thus prepared is transferred a carbon image in half-tone4 ,this pigment film1 when completely dry1 is flowed over with a mixture of-- ,glycerine #ce g4 ,water #be g4 ,alum #b g4 and this should be allowed to act for about five minutes and then removed with blotting-paper4 ,after this operation the pigment image can be easily destroyed4 ,the pigment image is now exposed to the action of a weak sandblast4 ,the sand acts on the relief image and gradually destroys it1 and so that the film of varnish underneath is gradually grained4 ,after the pigment film has been removed the picture shows in all its details in grain on the varnish of the stone or plate4 ,the image is now visible on the film of varnish1 according to the strength of the tones in partial graining1 and can be etched into the stone or plate4 ,this is effected by etching with phosphoric acid-- ,water #ajj g4 ,phosphoric acid #d g4 ,when the etching solution has acted for about two minutes1 the stone is washed and coated with a solution of gum-- ,water #ajj g4 ,gum arabic #e g4 and allowed to dry4 ,then the film of varnish is removed with a pad of cotton wool damped with turpentine1 the dry stone rolled up with litho ink1 damped1 and the excess of ink rolled off4 ,the picture now shows with all its finest details on the stone1 and can be printed4 ,in preparing a relief printing plate the film of varnish forms the resist for the first etching4 ,it is then rolled up and etched in the usual way4 ,for preparing larger pictures on stone or metal plates1 in which the grain must be coarser than with small pictures1 the fully-developed and still damp pigment image is dusted with powdered resin and the film allowed to dry with the powder adhering to it4 ,the pigment image thus dusted is treated1 as previously described1 with alum and glycerine1 exposed to the action of the sandblast1 and then etched with phosphoric or nitric acid4 ,as the soft pigment film receives a grain by the dusting1 this is reproduced of the same size by the action of the sandblast on the film of varnish on the stone or plate4 ,the principal points of this process of preparing photo-lithographs or phototypes in half-tone1 with a grain1 are as follows3-- #a4 ,from the photographic negative a pigment image is taken #gi and transferred to a litho stone or zinc plate1 which has been previously coated with varnish4 #b4 ,the pigment image is then exposed to the action of the sandblast2 and #c4 ,then the pigment image is removed1 and the image obtained on the film of varnish is etched4 ,in the ,k4,k4 ,hof und ,staatsdruckerei photo-lithographs as well as phototypes have been prepared with excellent results by this process4 ,the former in result are similar to the productions of the ,orell and ,fssli process1 and the latter were noticeable for good gradation4 ,on the other hand1 it cannot be denied that this process1 which is patented1 has been already surpassed by autotypy1 which is far simpler and easier to work1 and is founded on a scientific basis4 7,d47 ,,litho-,,heliogravure4 ,this process1 invented by ,chas4 ,eckstein1 of ,hague1 the general director of the ,topographical ,bureau of the ,royal ,netherland ,general ,staff1 also belongs to those processes of photo-lithography by means of which any picture in half-tone can be reproduced4 ,the breaking up of the half-tones is effected1 as with the autotypic methods1 by the use of a lineature1 but instead of this being done in the photographic exposure1 it is effected direct on the stone before the transfer of the photographic image4 ,in this particular process the stone itself is not coated with a light sensitive film and printed on direct1 but the ruling is made on the stone1 and then a negative pigment image--a diapositive--is transferred to it exactly the same as with photogravure on copper4 ,a further feature is that the result is not an ordinary transfer stone result1 but an intaglio etched stone1 which is printed from the depressions4 ,for this original process the basis is a ruled pattern stone1 prepared with great care and accuracy4 ,for preparing this a grey stone of the best quality should be taken1 and one without any chalky spots1 crystals1 or holes4 ,this should be polished with a coarse cloth and oxalic acid solution till it has a very high polish4 ,on the highly-polished stone surface is spread a very thin but even film of asphalt4 ,the solution is composed of-- ,asphalt #e parts4 ,white wax #f parts4 ,stearic acid #f parts4 ,this mixture is boiled1 and to it whilst boiling is added in drops a solution of two parts of soda4 ,when cold this mixture1 which is fairly hard1 is dissolved in about an equal volume of turpentine1 filtered and kept in bottles for use4 ,a sufficient quantity of this asphalt solution1 which must not be sensitive to light1 is poured into the middle of a levelled stone and #hj distributed by means of a lithographic ink roller1 which must not be used for any other purpose but this1 till the coating is absolutely even and shows a light brown colour4 ,when this film has become quite hard1 fine parallel lines are drawn over the whole surface of the stone with a very accurate working ruling machine1 by means of which from five to ten lines per millimetre can be ruled4 ,when the ruling is finished the stone is given a margin of wax1 and quickly and evenly flooded with the following etching fluid-- ,pure nitric acid #jaf parts4 ,alcohol #cf per cent4 #jfj parts4 ,water #ce parts4 ,and1 watch in hand1 is etched for about half-a-minute4 ,instead of the above a solution of-- ,glacial acetic acid #b g4 ,water #ajj g4 may be used and allowed to act for half-a-minute4 ,the stone is then well washed under a strong stream of water1 allowed to dry1 and covered with linseed oil4 ,after about five minutes the whole of the stone may be washed with turpentine4 ,then it should be inked up with a pad1 care being taken that all lines take the ink well and evenly4 ,this pattern stone serves as the original plate for the subsequent ruled transfer4 ,from the original ruled stone can be made1 according to the nature of the original1 a single1 double1 triple1 or four-fold transfer4 ,for preparing a stone with a ruled transfer1 a smoothly ground stone well polished with oxalic acid is evenly coated with sensitive asphalt solution4 ,on this1 when dry1 the desired single or crossed transfer from the original stone is made1 and dusted with bronze powder4 ,this adheres to the lines of the pattern1 and in combination with the printing ink protects the asphalt film underneath from the action of light4 ,during the subsequent exposure1 which1 according to the sensitiveness of the asphalt and intensity of the light1 can last from a half to two hours or more1 the particles of asphalt not covered by the bronze powder become insoluble1 whilst the protected parts preserve their solubility4 ,after correct exposure the surface of the stone is carefully washed with a tuft of cotton wool soaked in oil of turpentine1 when the particles of asphalt underlying the bronzed lines dissolve4 ,the stone at these parts is laid quite bare1 and therefore made capable of being subsequently etched4 ,the deep etching of the pattern is effected in the same way as was suggested in the preparation of the mother pattern stone4 ,by this method a positive pattern is obtained1 that is to say1 the lines print1 and the impression shows therefore a black network4 ,a second method of making a pattern transfer consists in making a pull from the original stone on to chalk transfer paper4 #ha ,this pull is then damped on the back1 and when just properly damp is laid on the polished stone 7without any asphalt7 and the transfer made4 ,in order to remove the chalk paper without damaging the pattern the stone is covered with warm water1 when the lines will dissolve4 ,the simple pattern will now be found on the stone1 which should now be well washed1 then dusted with resin powder1 which should be melted on with ether vapour4 ,then if the direction of the first lines was vertical1 the second transfer is arranged with the direction of the lines horizontal to the first1 and there is thus obtained a simple crossed pattern4 ,with four-fold crossed patterns the subsequent pulls are made in opposite diagonal directions4 ,after each transfer the stone is well washed1 allowed to dry1 then dusted with resin powder1 and with ether melted on to the pattern4 ,the stone is now deep etched with dilute nitric or acetic acid and covered with linseed oil4 ,by this method a grain instead of lines is obtained4 ,by polishing the stone and transferring on to it1 as well as by etching the places not covered by the ink1 we have the pattern reversed1 that is to say1 it is converted into grain4 ,for further operations of litho-heliogravure a very clear and soft negative is required1 from which a glass transparency is taken4 ,under this transparency pigment paper sensitized on a #bj per cent4 solution of potassium bichromate is printed to #h or #aj degrees ,vogel4 ,printing must be very carefully performed1 as with under-printing too many details are lost4 ,the exposed pigmented paper is washed in cold water1 laid film side down on the previously prepared stone1 and pressed into contact with an india-rubber squeegee4 ,it should then be allowed to dry in a not too dry or too warm place4 ,the stone should now be placed in a trough with warm water of about #dj to #de ,c41 and care should be taken to obtain water of as even a temperature as possible4 ,after about five minutes the paper will be free from the stone1 which should remain in the bath and be developed so long by shaking in order that the water may flow evenly over it till the image appears quite distinct2 a negative image is thus obtained on the stone4 ,the film is then allowed to dry spontaneously for four or five hours till the pigment image has become quite hard4 ,for etching a solution of perchloride of iron of various strengths is used1 #dj1 #cg1 #cc1 and #cj ,beaum4 ,with subjects very rich in tones all four will be used2 with simpler subjects one or the other may be omitted4 ,the etching will begin1 as a rule1 with the #dj solution4 ,the ferric chloride will first dissolve the thin1 hardened pigment film and then go through the open lines of the pattern1 where it will attack the stone and etch the deepest parts4 ,slowly the ferric chloride dissolves also the thicker pigment #hb film--begins also to etch the stone there1 but less deeply4 ,to tell when the four solutions should be used in turn1 as well as the correct moment to interrupt the etching1 requires considerable experience4 ,the #cj solution1 the weakest of the ferric chloride solutions1 is used last1 and in consequence of the greater proportion of water possesses a solvent power for the whole of the light-hardened pigment film4 ,accurate directions as to how long the etching with the different solutions is to be continued cannot be given1 as this depends upon the character of the subject as well as upon the thickness of the pigment image4 ,it may be always assumed1 however1 that any individual etching ought to last under no circumstances longer than three to four minutes4 ,with well-covered stones the first etching should not be allowed to act so long as the last1 and vice-vers with less covered stones4 ,as soon as the image shows the correct character through the etching solution the stone should be brought under the tap in the trough and quickly washed with clean cold water4 ,the surface of the image should then be flowed over with oil of turpentine in order to remove the asphalt and gelatine film1 and finally well washed with the rose and allowed to dry4 ,the picture will be found deeply etched into the stone4 ,the stone is now smeared over with linseed oil1 inked up1 and further treated as in ordinary lithogravure4 ,in this process the negative pigment image is transferred to the stone and the printing image prepared by etching2 the formation of the grain is produced by the pattern printed either on a polished stone1 when it is converted into points1 or the transfer may be effected on to an asphalted polished stone1 when a network of lines will be obtained4 ,for dark subjects the latter process is better1 for lighter subjects the grain4 ,printing from such a plate has more similarities with etching printing than from stone2 the effect of the ink is very good and expressive4 ,various pictures executed by ,eckstein and in our establishment in one or more colours have proved the value of this process in practice4 ,the foregoing are the different photo-lithographic methods for obtaining printing images in half-tone1 and although in no way exhaustive1 yet it appears to me that they are practically the most important4 #hc ,,appendix4 #a4 ,,negative ,,transfer ,,with ,,bichromated ,,gelatine ,,paper4 ,the properties of bichromated gelatine paper can also be very well used for the so-called negative printing1 and this method offers many advantages4 ,in order to convert a positive printing image into a negative various methods may be used2 the most convenient for the lithographer is the following3--,a good litho stone is first ground in the ordinary way and then the surface rubbed with a pad and oxalic acid solution till it has a high glaze or polish4 ,on to this stone is then transferred a sharp impression in a non-greasy ink from the positive printing image4 ,according to the destination of the stone for large or small editions one of two processes may be adopted4 ,if a thousand or more pulls are required from the stone the transfer may be dusted with resin powder1 and this melted with the burning1 heating1 or ether process and the drawing etched in relief with #h to #ab nitric acid and gum4 ,then the stone may be well washed with water and the acid removed with one to two per cent4 acetic acid4 ,for small runs the first etching is omitted1 and the stone treated with acetic acid4 ,in both cases the stone should be well washed1 dried1 and then coated with dissolved lithographic tusch or autographic ink4 ,the greasy substances of these materials penetrate into the surfaces of the stone that are laid bare1 and firmly adhere4 ,when the tusch or ink is completely dry the stone is washed with turpentine1 inked up1 and one now has a negative image from the subject in question1 which shows all the original printing places in white and all white places black4 ,the process of preparing such negative prints by the use of bichromated gelatine papers is much simpler4 ,a sheet of gelatinized paper is sensitized for this purpose on a #e per cent4 bath of potassium bichromate1 squeegeed to a sheet of plate-glass and well dried1 and on this is made with black ink1 which is very opaque1 in the dark or in gaslight1 a sharp clean print4 ,this print is then laid on a flat cable1 under a sheet of plate-glass1 so that it cannot roll up1 and exposed to the light for from five to thirty minutes4 ,a long exposure rarely does harm in such cases1 as the good opaque black ink allows no rays of light to pass through to those places which later should print white4 ,the next manipulation is the development and inking up1 which is done as in ordinary photo-lithography4 ,in this operation all #hd those places which were not covered up by the printing will take the developing ink2 on the other hand1 those places where the impression was will wash out clean and white4 ,the print has assumed the appearance of a photographic positive4 ,the print is now treated like any other photo-lithographic print1 and finally transferred to a stone or zinc plate4 ,this method is distinguished by its simplicity and safety2 it has also the advantage that any desired printing subject can be directly transferred in negative form to a zinc plate for relief etching1 which otherwise could only be done by preliminary transfer to stone and subsequent transfer to zinc4 #b4 ,,photo-,,autography4 ,,drawing ,,with ,,autographic ,,ink ,,or ,,lithographic ,,chalk ,,on ,a ,,cyanotype1 ,,salted ,,or ,,other ,,print ,,from ,a ,,photographic ,,negative ,,or ,,positive4 ,by autography we understand that method of reproduction by which any writing or drawing is made on a prepared or not prepared paper with greasy ink1 tusch or chalk1 which is subsequently transferred to stone or zinc for printing1 or to zinc plates for relief etching4 ,autographic drawing papers differ for the different purposes1 and for writing and simple line drawings smooth hard post paper is used1 and lined transfer paper for fine pen or chalk drawings4 ,the latter are prepared commercially by ,angerer and ,gschl4 ,very beautiful grained drawings can also be made for transfer on pyramidal grain paper4 ,the proof for such drawings is usually done with lead pencil or red chalk1 or it may also be made on a gelatine proof4 ,in order to obtain fully and completely the character and correct reproduction of the drawing1 without special expense of artistic help1 it is advisable to use a photographic print as proof4 ,it should be noted that for pen drawing on smooth paper with greasy tusch or ink1 for chalk drawings on a prepared grained paper done as previously mentioned1 with greasy lithographic chalk1 the drawing should be transferred direct to zinc or stone in order to save having to make subsequently a photographic print4 ,if a pencil1 red crayon1 or other proof is used for an autographic drawing on paper with the idea of transferring it direct to stone or zinc1 a suitable photographic print may also be used on suitable paper without any disadvantages4 ,for the prints all photographic papers without glaze1 such as ordinary plain salted paper1 ,eastman's positive bromide paper1 and others1 may generally be used4 ,glossy or albumenized papers are not suitable for this1 as the ink runs1 and does not form solid clean lines4 #he ,the best of all1 however1 is cyanotype paper1 as even with very deep printing it keeps the details in the shadows open1 and on account of its blue tones is more suitable for the subsequent drawing with black tusch4 ,when1 however1 prussiate paper is not handy1 and subjects with fewer shadows and less details are to be treated1 any of the other papers above-mentioned may be used4 ,if ferro-prussiate paper is to be used1 the same may be prepared as recommended on p4 #bc4 ,the so-called salted or plain paper is prepared as follows3--,a sheet of well-sized post paper is first bathed in a solution of-- ,ordinary salt #a part ,water #be parts and then sensitized in a solution of silver nitrate #a 3 #ab4 ,it is printed till the print has assumed a fairly full brown tone1 and all the details in the shadows are well printed out4 ,it should then be toned in the following toning bath3-- ,distilled water #ajjj g4 ,sodium acetate 7twice fused7 #ae g4 ,solution of gold chloride 7#a 3 #ajj7 #be g4 till the print has assumed a deep dark brown tone4 ,it should then be fixed in a solution of sodium hyposulphite1 #a 3 #ae4 ,it should be printed rather deep1 as in toning and fixing the image loses in depth4 ,it is moreover unnecessary in this case to make a beautiful print2 the chief thing is only that all details of the image should be clearly seen4 ,the print is then well washed in frequent changes of water and then dried4 ,the print on ,eastman's bromide paper is prepared as follows3-- ,red light must be used4 ,it should be printed by an ordinary gas flame at a distance of about #ej-hj cm4 7 #bd to #cf ins47 for #a to #bj seconds1 according to the density of the negative4 ,here again a technically perfect print need not be arrived at1 but one which contains all the details very clear4 ,under a good transparent negative a useful image for the artist will be obtained with about two seconds' exposure4 ,the developer is composed of two solutions3-- 7,a47 ,water #ejj g4 ,neutral oxalate of potash #afe g4 7,b47 ,water #ej cm4 ,sulphate of iron #ae cm4 ,concentrated sulphuric acid #b drops ,or glacial acetic acid #e drops ,three parts of solution ,a and one part of solution ,b should be #hf mixed together4 ,as soon as the shadows have attained the desired tone1 the prints should be placed in several fresh baths of ,water #bjj ccm4 ,acetic acid #a drachm4 ,sat4 sol4 alum #ej g4 and then washed and fixed in a bath of ,water #ej ccm4 ,sodium hyposulphite #aj g4 for about ten minutes4 ,then well washed and dried4 ,for pen drawings all not gelatinized or albumenized printing papers may be used as already mentioned4 ,the chief thing is that the paper should be well-sized and of good firm texture4 ,if prepared grain paper is used1 which is provided with a film of chalk1 kaolin1 or any other white colouring matter combined with gelatine1 and on which film the grain is impressed1 only prussiate prints can be used4 ,the paper is sensitized as previously described1 only it is advisable not to leave it too long in the solutions1 or else the film may become softened4 ,the film will also dissolve in hot water at about #hj ,c4 ,the prints as soon as dry can be used for drawing on4 ,on the grain papers the outline may be drawn with the pen and be shaded with chalk1 or it may be drawn with chalk only4 ,with unprepared papers it is advisable to coat them with a thin solution of boiled starch1 as then the transfer to zinc or stone is most exact4 ,the drawing may also be left a long time without spoiling4 ,the coating is performed with a pad dipped into the liquid1 which consists of one part of fine bookbinder's starch and four or five parts of water1 and passed several times over the print4 ,the drawings ought only to be done with greasy lithographic tusch or chalk or autographic ink1 which consists principally of greasy materials and lampblack4 ,for pen drawings hard pens should be used1 and care must be taken to make thick strokes4 ,only a little tusch or ink ought to be taken into the pen1 so that it does not run out1 and thus clean1 sharp lines be obtained4 ,if this be observed very close shadings and cross lines can be produced clean and neat4 ,when the drawing is finished and the tusch or ink has become dry the same should be laid between damp blotting-paper1 and meanwhile a clean ground1 and dry pumiced stone worked in the press and the pressure correctly adjusted4 ,as soon as the drawing has become moderately damp right through1 and the paper feels soft without being wet1 it should be laid with the image downwards on the stone and transferred to the same with strong pressure4 ,after repeated working the paper will adhere firmly to the stone4 ,in order to loosen it the stone should be covered with hot water of about #hj ,c41 when the film will dissolve and the paper become quite free4 ,any exertion of force must in this #hg operation be quite avoided1 and the paper must not be pulled off with violence4 ,all1 even the finest lines1 will have been transferred to the stone4 ,the stone is now gummed1 if possible allowed to stand for some hours1 and then etched with a gum etching solution of two degrees' acid strength1 or later etched in relief1 and is ready for printing4 ,if the transfer is made to zinc1 for printing from this the plate is treated as suggested on p4 #f4 ,if1 however1 a relief etching for the typographic press is to be prepared of the subject1 the transfer is made on to a smooth polished zinc plate4 #c4 ,,lithogravure4 ,with this particular process an intaglio printing stone or intaglio printing plate is prepared by chemico-physical means4 ,this process was discovered and brought to great perfection by ,chas4 ,eckstein1 the general director of the ,typographical ,bureau at the ,hague1 and offers especially many advantages for the reproduction of maps4 ,a map engraved1 drawn1 or transferred on stone1 or written in on copper1 in originally one colour1 can by this process in a comparatively easy way be converted into a many-coloured print2 this process can also be used very advantageously for changing the names for the places--rivers1 mountains1 etc4 ,in the first place intaglio original printing plates in all the colours can be prepared which can then be printed for further reproduction2 in the second case it is necessary to re-engrave the network1 hydrography1 etc4 ,when it is desired to convert a monochrome image into a multi-coloured map1 as many stones as there are colours to be used must be first ground and polished with oxalic acid till they have a high polish4 ,in the meantime an asphalt or other light-sensitive solution should be prepared1 with which the stone is coated in the dark very evenly1 and somewhat more than is done for a photo-lithographic print4 ,the asphalt solution is composed of-- ,syrian asphalt #bj g4 ,chloroform #cjj g4 ,benzole #ajj g4 ,oil of lavender #bj drops4 ,after it has been dried in the dark the impression from the black plate1 which should be previously made on transfer paper1 is transferred to the asphalt film as previously laid down1 and before it is dry dusted with bronze powder4 ,all lines1 titles1 or figures which should not appear on that particular colour-plate must be then covered with the above asphalt solution1 and only those places1 for example1 on the one plate all titles1 on another all the roads1 on a third the river courses1 and so on1 should be left1 all of which later should appear in printing4 #hh ,the stone is now1 according to the sensitiveness of the film and the strength of the light1 exposed for from fifteen minutes to two hours4 ,over-printing1 if it is not very exorbitant1 does not do any harm with the stronger letters or lines on account of the good covering4 ,with very fine lines1 however1 more care must be taken4 ,if there is any doubt as to the length of the exposure a test may be made at one corner of the plate with a pad dipped in rectified turpentine4 ,when the asphalt will no longer dissolve the exposure may be discontinued4 ,with some experience the photometer may also be used4 ,then the whole surface should be washed with rectified turpentine and a pad of cotton wool1 when the ink lying under the bronze1 that is1 the lines where the asphalt has been protected from the action of light dissolve1 and the surface of the stone appears4 ,the rest of the asphalt film has become insoluble from the action of light1 and now forms the etching-ground for the reversed negative image on the surface of the stone4 ,when the stone has been well washed with water it may be etched1 which is done with glacial acetic acid two parts1 water #ajj4 ,when there are any fine lines in the drawing the etching is interrupted at the end of two minutes1 and they should then be covered with tusch1 and then when the tusch is dry the other parts are further etched for a longer or shorter time according to the degree of fineness4 ,in any case the time of etching should not exceed five minutes4 ,the stone is allowed to dry and then coated with a solution of tusch or linseed oil1 which penetrates into the etched parts and makes them capable of taking ink4 ,after about ten minutes the whole stone should be washed with turpentine or benzole1 by which the etching ground is removed1 when the stone is inked up like an ordinary gravure4 ,in this way is obtained a stone with deep etched drawing1 which according to the blocking contains the titles1 the rivers or roadways1 and from which subsequently the necessary gravures can be taken4 ,this stone can either be used for direct printing or it may be used as an original stone from which the necessary transfer can be made4 ,the same process may also be made for intaglio printing plates on zinc or copper1 only then the etching must be done with nitric acid or ferric chloride4 ,instead of the transfer on the light sensitive film1 a drawing on transparent paper may be used1 or a photographic transparency4 ,the exposure in this case1 as the opaque ink and bronze powder are not used1 must be very carefully estimated4 ,the advantage of this process is that an intaglio printing surface may be obtained so that engraving is entirely or partially avoided1 and that this printing surface may be used as an original from which the reproductions are made4 #hi ,,scraper ,,boards1 ,,manufactured ,,by ,,augerer ,g,,schl1 ,,vienna4 ,no4 #f4--;,a white scraper board printed with black lines4 ,there are #dj black and #dj white lines to the centimetre2 the ratio of black to white is as #a 3 #b4 ,at right angles to the black lines impressed lines are arranged1 of which #cg are depressed and #cg raised up to the square centimetre4 ,no4 #g4--,this is practically the same as ,no4 #f1 only that the lines are slightly less in number1 namely1 #ce black and #ce white and #bf impressed lines in equal areas to ,no4 #f4 ,no4 #h4--,this contains dots instead of lines1 both black and impressed2 there are #a1aef black dots at regular intervals1 and #ifa impressed dots to the square centimetre4 ,no4 #i is a smooth scraper board4 ,nos4 #aj and #aa4--,these are impressed with straight lines in the proportion of #a 3 #a4 ,with ,no4 #aj there are #bg lines1 in ,no4 #aa1 #cg lines to the centimetre4 ,nos4 #ab and #ac4--,these are impressed with lines at right angles to one another1 so that regular squares are formed4 ,no4 #aa contains #gcj1 ,no4 #ab1 #a1cgj squares in every square centimetre4 ,illustration ,,index4 ,acid1 ,acetic1 #aj ,citric1 #aj ,gallic1 #aj ,hydrochloric1 #i ,nitric1 #i ,oxalic1 #aj ,phosphoric1 #aj ,sulphuric1 #i ,action of ,lineature1 #fi ,albert's ,photo-litho ,paper1 #ef ,albumen ,process1 #fd ,angerer ,gschl1 #be ,asphalt1 #ag ,process1 #fj ,husnik's1 #fj ,valenta's1 #fa ,autographic ,ink1 #g ,autotypy1 #fg ,negative1 #da ,barts' ,process1 #bj1 #gg ,behaviour of ,asphalt on ,stone1 #h ,cadmium ,intensification1 #dj ,chromate ,salts1 #dh ,coating the ,stone1 #fb ,cold ,melting ,process1 #ab ,correcting ,negatives1 #ce ,cyanotype ,paper1 #bd ,bleaching1 #bd ,dark ,room1 ,the1 #cd ,deep-etching ,process1 #aa ,developer1 #cg ,developing ,ink1 #h ,direct ,printing1 #fj ,transfer1 #ae ,distance of ,lineature1 #gc ,drawing on ,blue ,prints1 #bc ,prepared ,paper1 #be ,eberle's ,process1 #aa ,eckstein's ,process1 #bj ,electric ,lamps1 #ca ,etching the ,stone1 #aj ,failures in ,transfers1 #eh ,fixing1 #ch ,fox ,talbot1 #ag ,franz's ,paper1 #ee ,galls1 ,tincture of1 #aj ,gelatinizing ,paper1 #dg ,general ,notes on ,photo-lithography1 #di ,gold and ,mercury ,intensifier1 #ch ,greasy ,drawing ,materials1 #f ,gum ,arabic1 #aj ,half-tone1 ,breaking up1 #bj ,photo-lithography1 #fg ,hebensperger's ,process1 #ff ,hbl's ,hydroquinone ,intensifier1 #ch ,iso ,emulsion1 #dc ,husnik's ,asphalt1 #ag ,photo-litho ,paper1 #ec ,hydroquinone ,developer1 #db ,indirect ,transfer1 #af ,inking up and ,developing1 #ea ,intensification1 #cg ,intensifier1 ,lead1 #dj ,mercury1 #dj ,metol1 #ci ,silver1 #dj ,uranium1 #dj ,iodized ,collodion1 #cg ,isochromatic ,emulsion1 ,albert1 #da ,hubl1 #dc ,lemercier and ,lerebours1 #af ,line ,drawings1 #ba ,litho ,chalk1 ,hard1 #g ,soft1 #h ,stone1 #d ,lithogravure1 #hg ,litho-,heliogravure1 #gi ,lithography1 ,theory of1 #c ,making ,direct ,negatives1 #cf ,mungo1 ,ponton1 #ag ,negative for ,photo-litho1 #cd ,transfer with ,paper1 #hc ,negr1 #ag ,nicephore1 ,nipce1 #af ,orell and ,fssli ,process1 #bj1 #ge ,photo-,autography1 #hd ,photo-,litho ,transfer1 #eg ,photometer1 #ea ,poitevin1 #ag ,prism1 #dd ,printing1 #fb on ,bichromated ,gelatine1 #ej ,pyramidal ,grain ,paper1 #bf ,reproduction of ,prints1 #bg ,size of1 #bh ,reversed ,negatives1 #dd ,sacher's ,fish-glue ,process1 #ff ,scamoni's ,process1 #ab ,scraper ,boards1 #be ,schuffelen ,co41 #bf ,sensitizing ,paper1 #di ,silver ,bath1 #cg ,stripping ,negatives1 #de ,studio1 ,the1 #cj ,tusch1 #g ,valenta's ,asphalt1 #ag ,waterhouse's ,arrowroot ,process1 #ff ,wezel ,naumann1 #ge ,zinc ,plates1 #e ,roughened1 #f ,oxidized1 #f ,illustration ,,advertisements advertisement ,monthly1 ,price #f;d4 ,post ,free1 #h;d4 ,per ,annum1 post free1 #h- ,illustration3 ,,the ,process-,photogram ,the only journal specially devoted to the interests of ,photo-mechanical workers4 ,a ,phenomenal ,success4 ,mr4 ,,allan ,w4 ,,seward1 of ,montclair1 ,n4,j41 says3--8,altho' an old process-worker ,i will not do without the ,,process ,,photogram40 ,dr4 ,j4 ,h4 ,,smith1 of ,zurich1 says3--8,i am pleased to find you are bringing out a ,,process ,,photogram4 ,i have no doubt it will be a success40 ,mr4 ,,john ,,cummings1 of ,alloa1 ,n4,b41 a beginner in process-work1 says3--8,your magazine is splendid40 ,,limited ,,issue4 ,order at once from any ,newsagent or ,photo ,material ,dealer1 or at post free prices from the ,publishers4 _/advertisement advertisement ,monthly1 ,price #c;d4 ,post ,free1 #d;d4 ,,devoted ,,to ,,photographic ,,work4 ,illustration3 ,,the ,photogram ,,editors3 ,h4 ,,snowden ,,ward4 ,,catharine ,,weed ,,ward4 ,,permanent ,,staff3 ,,charles ,w4 ,,gamble4 ,,schriftf,,hrer4 ,w4 ,,ethelbert ,,henry1 ,c4 ,e4 ,w4 ,t4 ,,whitehead4 ,has the largest circulation of any ,photographic ,journal4 ,contains each month supplements of great value to photographers and process men4 8,far and away ahead of its photographic contemporaries40--,optician4 8,the ,,photogram smacks of smartness4 ,is smartly edited1 excellently arranged1 and very tasteful in type and graphic dress1 as well as being much better printed and on better paper than any of the photographic journals of home production40--,the ,british ,lithographer4 8,simply invaluable to all who are interested in photography40--,book and ,news ,trades ,gazette4 8,the ,,photogram is a remarkable production1 both in letterpress and illustrations40--,sheffield ,telegraph4 8,the first volume of the ,,photogram has been one of remarkable excellence1 both in its matter and illustrations40--,liverpool ,courier4 8,it is a marvel 4 4 4 4 highly interesting matter1 and filled with illustrations4 ,the style1 get up1 and printing are all high class40--,the ,photographer4 ,,dawbarn ,,ward1 ,limited1 #f1 ,,farringdon ,,avenue1 ,,london1 ,e4,c4 _/advertisement advertisement ,the ,photogram ,annual4 ,illustration3 ,photograms of '#ie4 ,price #as4 nett4 ,post ,free #as4 #f;d4 ,in ,america and abroad4 ,post ,free #bs4 or #ej cents4 ,ready about ,october #bjth4 ,a ,,pictorial ,,and ,,literary ,,record ,of the ,best ,photographic ,work of the ,year4 ,arranged by the ,editors and ,staff of 8,,the ,,photogram40 ,to be followed next year by 8,photograms of '#if40 ,,photograms ,,of '#ie aims to represent modern photography as 8,royal ,academy ,pictures10 8,pictures of the ,year10 c41 represent the arts of painting and sculpture4 ,,the ,,work consists of #if pages1 super-royal #hvo 7#i by #f71 and is printed on heavy 8art printing0 paper4 ,,the ,,illustrations are the finest possible photo-mechanical 7half-tone7 reproductions1 and are made by the ,,meisenbach ,,co41 ,west ,norwood4 ,there are about thirty full-page reproductions1 and the same number of smaller sizes1 mostly half-page1 as well as ,,four ,,chemigraph ,,supplements1 printed by the ,,national ,,chemigraph ,,co41 of ,st4 ,louis1 ,new ,york1 and ,chicago1 ,u4,s4,a41 and mounted on handsome boards4 ,they represent the four principal imitations of pure photography by photo-mechanical process1 and as the work of the ,,national ,,chemigraph ,,co4 has not been published in ,england1 will be a revelation to photographers and photo-mechanical workers alike1 of the latest possibilities in 8process0 work4 ,it will be quite impossible to repeat these supplements1 and therefore impossible to supply any copies that may be demanded after the first edition is exhausted4 ,,the ,,literary ,,portion of the work includes critical notices of the two great ,british ,photographic ,exhibitions1 and special articles on the work of the year in the ,english-speaking countries and colonies by some of the best-qualified writers in each country4 ,amongst them are ,,british ,,isles3--,,gleeson ,,white1 assisted by the staff of ,the ,photogram4 ,,united ,,states3--,,alfred ,,stieglitz1 ,editor of ,the ,american ,amateur ,photographer4 ,,canada3--,a4 ,m4 ,,cunningham1 ,president of ,the ,photographic ,association of ,canada4 ,,the ,,british ,,exhibitions of ,the ,royal ,photographic ,society and ,the ,salon have supplied most of the originals for reproduction1 but some of the gems of the provincial exhibitions are also included4 ,,non-,,exhibited ,,pictures are represented as far as possible1 for the aim is to embrace the whole field of the year's work4 ,,american1 ,,colonial1 ,c41 work is represented by a few typical pictures1 selected by the gentlemen who supply the matter dealing with the work of the various countries4 ,,the ,,scientific ,,and ,,practical applications of photography are not ignored1 though the bulk of the space is devoted to art works4 ,some of the latest achievements in astronomy1 microscopy1 c41 are illustrated by reproductions of the finest recent work4 ,,the ,,edition ,,is ,,limited to #aj1jjj copies4 ,order early4 ,ready ,october #bjth4 ,published for 8,,the ,,photogram0 ,ltd4 ,,london3--,,dawbarn ,,ward1 ,,ltd41 ,farringdon ,avenue1 ,e4,c4 ,,new ,,york3--,,spon ,,chamberlain1 #ab1 ,cortlandt ,street4 ,,philadelphia3--,w4 ,p4 ,,buchanan1 #abbf1 ,arch ,street4 _/advertisement advertisement ,,ross' ,,lenses ,still take the lead for high-class work1 and are universally used by process workers4 ,illustration ,illustration ,,new ,,catalogue ,,of ,,ross' ,,ross-,,zeiss ,,and ,,ross-,,goerz ,,lenses ,,now ,,ready4 ,do not fail to send for a copy4 ,it also contains full particulars of ,,reversing ,,prisms and ,,mirrors1 ,,process ,,cameras1 ,and all kinds of ,photographic ,apparatus and ,materials4 ,illustration ,illustration ,,ross ,,co4 #aaa1 ,new ,bond ,st41 ,london1 ,w4 _/advertisement advertisement ,crown #hvo41 ,illustrated1 #as4 net1 ,post free1 #as4 #b;d42 ,cloth1 #as4 #f;d4 net1 ,post free1 #as4 #h;d4 ,illustration3 ,photo-,ceramics ,photography applied to the decoration of ,plaques1 ,pottery1 and other ,ceramic and ,metallic surfaces4 ,,by ,w4 ,,ethelbert ,,henry1 ,c4,e41 and ,h4 ,,snowden ,,ward ,both of the staff of ,the ,photogram4 _/advertisement advertisement ,cloth ,gilt4 ,price #abs4 #f;d4 net4 ,post free1 #acs4 ,illustration3 ,cyclopdic ,photography ,a ,complete ,handbook of the ,terms1 ,processes1 ,formul1 and ,appliances available for ,photography1 arranged in ,cyclopdic ,form for ready reference4 ,,by ,,edward ,l4 ,,wilson1 ,,ph4,d41 ,editor of 8,wilson's ,photographic ,magazine02 ,author of 8,wilson's ,photographics10 8,wilson's ,quarter ,century in ,photography10 8,photographic ,mosaics10 c4 ,of all ,photographic ,dealers or ,booksellers1 ,,and ,,dawbarn ,,ward1 ,ltd41 #f1 ,,farringdon ,,avenue1 ,,london1 ,e4,c4 7,a ,complete ,list of ,photographic ,works1 post free1 on application47 _/advertisement advertisement ,photo-,lithographic ,materials4 ,the most ,complete ,stock is kept by ,,penrose ,co41 ,the ,photo-,process ,stores1 #h #h;a1 ,upper ,baker ,street1 ,clerkenwell1 ,,london4 ,sole ,agents for ,,jafee',s ,,photo-,,litho ,,papers ,for ,line and ,half-,tone4 ,,albert',s ,,husnik',s ,papers also ,stocked4 ,,saxe1 ,,rives1 ,,and ,,bank-,,post ,,plain ,,papers4 ,full ,stock always on hand of ,,angerer ,,scraper ,,boards4 ,polished or ,grained ,zinc ,plates in great variety4 ,velvet1 ,leather1 ,indiarubber and ,compo ,rollers4 ,photo-,transfer ,ink4 ,waxed ,asphaltum4 ,all ,tools and ,sundries4 ,,sole ,,agents ,,for ,,max ,,levy',s ,,perfected ,,screens4 ,a ,selection of ,rulings suitable for ,photo-,litho usually on hand4 ,new and ,complete ,catalogue for all ,processes1 #f;d4 post free4 _/advertisement advertisement ,,bernhard ,,wachtl1 ,,vienna 7,,austria71 ,,vii_/#b ,,kirchberggasse #cg4 ,,all ,,requirements ,,for ,,workers ,,in ,photo-,mechanical ,processes4 ,specialities for ,photo-,lithography1 ,photo-,zinco in ,line and ,half-,tone1 ,photogravure1 ,collotype1 etc4 ,screens1 ,special ,cameras1 ,lenses1 ,chemicals1 ,inks1 ,zinc and ,copper ,plates1 ,tools1 ,machinery1 all ,appliances for ,process ,work4 ,studios completely fitted4 _/advertisement advertisement ,,german ,,gelatine ,,works4 ,hoechst o_/,main ,schweinfurt1 ,,manufacturers ,,of ,,gelatine for ,,photo-,,lithography4 ,brands3 ,,heinrich',s ,,drescher4 ,,wholesale ,,agents3 ,a4 ,m4 ,,zimmermann1 #f and #g1 ,,cross ,,lane1 ,,london1 ,e4,c4 _/advertisement advertisement ,collotype ,steam ,presses4 ,these steam presses1 which have been used with excellent results for many years in the first collotype establishments of all countries1 and which contain all the latest improvements1 are supplied by the makers with the guarantee of the highest and most complete power of working4 ,by means of the most solid construction and the best and faultless make of these ,collotype ,steam ,presses1 the finest results have been attained4 ,the arrangement of the duplicate inking of the printing plate1 as well as the double pressure of the sheet1 is suitable for the most difficult work4 ,the saving of time by the arrangement is a great advantage of these machines4 ,illustration ,when desired these presses can be fitted with automatic mask and laying-on table2 they can also be arranged for lithography without the automatic mask and table1 but with feeding apparatus4 ,the newest discovery1 a contrivance for mechanically damping the printing plate1 patented in all civilized countries1 can be supplied to order4 ,,our ,,machines ,,are ,,in ,,use ,,by ,,all ,,the ,,first-,,class ,,collotype ,,printers ,,in ,,the ,,world2 ,,about #ajj ,,machines ,,being ,,in ,,use ,,in ,,england ,,alone4 ,,lithographic ,,steam ,,presses1 in all sizes4 ,,steam ,,presses ,,for ,,zincography1 in three sizes4 ,,bronzing ,,machines1 four sizes of approved construction4 ,,card-,,bronzing ,,machines1 for stout cards and boards1 c4 ,manufacturers3 ,,schmiers1 ,,werner ,,stein1 ,leipzig4 ,sole ,agent for the ,united ,kingdom3 ,f4 ,k,,hn ,co41 #fe_/f1 ,basinghall ,street1 ,london1 ,e4,c4 _/advertisement advertisement ,,demy #hvo41 ,,cloth4 ,,price #cs4 ,,net4 ,post ,free #cs4 #c;d4 ,illustration3 ,exterior and ,interior ,photography ,,by ,,frederick ,,wm4 ,,mills1 ,f4,r4,m4,s41 ,,author ,,of 8,the ,art and ,practice of ,interior ,photography10 8,photography for ,architects10 8,photography applied to the ,microscope10 8,an ,introduction to the ,study of the ,diatomace10 c4 ,,illustrated4 _/advertisement advertisement ,,demy #hvo41 #as4 ,,net4 ,,cloth1 #as4 #f;d4 ,,net4 ,postage #b;d4 ,illustration3 ,stenopaic or ,pin-hole ,photography ,with ,exposure and other ,tables4 ,,by ,,frederick ,,wm4 ,,mills1 ,f4,r4,m4,s4 ,,illustrated4 ,of all ,photographic ,dealers and ,booksellers or ,,dawbarn ,,ward1 ,,ltd41 #f1 ,,farringdon ,,avenue1 ,,london1 ,e4,c4 7,a ,complete ,list of ,photographic ,works post free on application47 _/advertisement advertisement ,,benj,n4 ,,winstone ,,sons ,,manufacturers1 #ajj1 #aja1 ,,shoe ,,lane1 ,,london1 ,e4,c4 ,printing ,inks and ,materials ,,for ,,all ,,photo-,,mechanical ,,processes4 ,lithographic ,presses1 ,lithographic ,inks1 ,,albert',s ,,photo-,,transfer ,,paper4 ,,husnik',s ,,photo-,,transfer ,,paper4 ,,photo-,,litho ,,transfer ,,ink1 ,,and ,ink specially made for use in ,etching ,zinc ,plates4 7,inks usually made for this purpose are apt to splutter47 ,rocking ,baths1 ,zinc and ,copper ,plates1 ,rollers1 ,,indiarubber1 ,,composition1 ,,leather1 ,,velvet ,,on ,,litho ,,stocks1 ,,or ,,in ,,letterpress ,,frames4 ,stippled1 ,ruled1 and ,dotted ,tint ,plates1 ,,and ,,all ,,other ,,printing ,,materials ,,for ,photo-,zincography1 ,photo-,lithography1 ,photo-,engraving1 ,photo-,type1 ,collotype1 and kindred processes4 _/advertisement advertisement ,demy #hvo4 ,cloth4 ,price #cs4 net4 ,post free1 #cs4 #f;d4 ,illustration3 ,a ,handbook of ,illustration ,by ,a4 ,,horsley ,,hinton4 ,with reproductions from ,photograms and ,sketches by the ,author and other ,artists4 _/advertisement advertisement ,cloth4 ,price #as4 net4 ,post free1 #as4 #a;d4 ,illustration3 ,the ,photographer's ,exposure ,book ,with ,tables of ,motion1 ,exposure1 c41 and other useful information1 and pages for ,recording ,exposures1 c4 ,,compiled ,,by ,,fred,k4 ,w,m4 ,,mills1 ,f4,r4,m4,s41 c4 ,,of ,,all ,,photographic ,,dealers ,,and ,,booksellers1 ,,or ,,dawbarn ,,ward1 ,ltd41 #f1 ,,farringdon ,,avenue1 ,,london1 ,e4,c4 7,complete ,list of ,photographic ,works1 post free1 on application47 _/advertisement advertisement ,illustration3 ,,trade ,,mark4 ,,klimsch ,,co41 ,,francfort o_/,m41 ,,germany1 ,manufacturers and ,suppliers of ,machinery1 ,materials and ,utensils ,,for ,,letterpress ,,and ,,lithographic ,,printers1 ,,lithographic ,,draughtsmen1 ,,wood ,,engravers1 ,,copper-,,plate ,,engravers1 ,,and ,,printers1 ,for ,,photo ,,engravers ,,and ,,collotype ,,printers4 ,,all ,,materials ,,for ,,photo-,,lithography4 ,,latest ,,novelty3 ,apparatus for inking copies upon ,photo-,lithographic ,paper4 ,illustration ,,in ,,two ,,sizes4 ,no4 #a4--,size of ,glass ,plate1 #ab by #af inches4--#afs4 ,no4 #b4--,size of ,glass ,plate1 #ai by #bc inches4--#a4 ,all sorts of ,grained and ,scraping ,papers1 ,photo-,lithographic ,transfer ,papers1 etc4 ,,ask ,,for ,,particulars ,,and ,,prices4 _/advertisement advertisement ,,dawbarn ,,ward1 ,,ltd4 ,undertake the ,publishing of all kinds of ,photographic ,literature1 and will be pleased to hear from all ,authors with a view to ,publishing for them or ,purchasing their ,copyrights4 ,they believe they already keep the most varied ,stock of ,photographic ,works of any ,firm in the ,world1 and will send a ,,complete ,,list1 ,,post ,,free1 upon application to #f1 ,,farringdon ,,avenue1 ,,london1 ,e4,c4 _/advertisement advertisement ,illustration3 ,i4 ,fr4 v4 ,lenbach pxt4 ,,photolithograph ,,from ,a ,,pen ,,and ,,ink ,,sketch4 ,,from ,,an ,,etching ,,published ,,by ,e4 ,,aum,,ller ,,in ,,munich4 ,,reproduction ,,and ,,print ,,by ,,the ,,imp4 ,,roy4 ,,state ,,printing ,,office ,,in ,,vienna4 _/advertisement advertisement ,illustration3 ,,ii4 ,gez4 ,ferd4 ,laufberger1 ,gest4 ,j4 ,sonnenleiter ,,photolithograph ,,from ,a ,,copper ,,plate ,,engraving4 ,,property ,,of ,,the ,,gesellschaft ,f,r ,,vervielf,,ltigende ,,kunst8 ,,in ,,vienna4 ,,reproduction ,,and ,,print ,,by ,,the ,,imp4 ,,roy4 ,,state ,,printing ,,office ,,in ,,vienna4 _/advertisement advertisement ,illustration3 ,,iii4 ,rud4 ,burnt del41 ,c4 ,angerer ,gschl chem4 ,,autotypy ,,from ,,an ,,original ,,drawing1 ,,from ,,the ,,work ,,the ,,austrian-,,hungarian ,,monarchy ,,in ,,word ,,and ,,picture84 ,,print ,,by ,,the ,,imp4 ,,roy4 ,,state ,,printing ,,office ,,in ,,vienna4 _/advertisement advertisement ,illustration3 ,,iv4 ,,positive ,,print ,,from ,a ,,pantograph4 ,,reproduction ,,and ,,print ,,by ,,the ,,imp4 ,,roy4 ,,state ,,printing ,,office ,,in ,,vienna4 _/advertisement advertisement ,illustration3 ,v4 ,,chromated ,,gelatine ,,negative ,,print ,,from ,a ,,pantograph4 ,,reproduction ,,and ,,print ,,by ,,the ,,imp4 ,,roy4 ,,state ,,printing ,,office ,,in ,,vienna4 _/advertisement advertisement ,illustration3 ,,vi4 ,hugo ,charlemont del4 ,,autographic ,,drawing ,,on ,a ,,blue ,,or ,,ferroprussiate ,,print4 ,,from ,,the ,,work ,,the ,,austrian-,,hungarian ,,monarchy ,,in ,,word ,,and ,,picture84 ,,reproduction ,,and ,,print ,,by ,,the ,,imp4 ,,roy4 ,,state ,,printing ,,office ,,in ,,vienna4 _/advertisement advertisement ,,angerer ,scraper ,boards4 ,illustration3 ,scraper ,boards with printed line tint4 ,no4 #f4 ,no4 #g4 ,illustration3 ,scraper ,board with ,printed ,stipple4 ,no4 #h4 ,enamel ,scraper ,board for pen and ink drawing4 ,no4 #i4 ,illustration3 ,scraper ,boards with single stamped lines4 ,no4 #aj4 ,no4 #aa4 ,illustration3 ,scraper ,boards with crossed stamped lines4 ,no4 #ab4 ,no4 #ac4 ,agents3 ,,penrose ,co4 ,the ,photo-,process ,stores1 #h #h;a4 ,upper ,baker ,street1 ,clerkenwell1 ,london4 _/advertisement ,,transcriber',s ,,note ,original spelling and grammar have been generally retained1 with some exceptions noted below4 ,original printed page numbers are shown like this3 #eb4 ,original small caps are now uppercase4 ,italics look like this4 ,footnotes have been relabeled #a-c1 and moved from within paragraphs to nearby locations between paragraphs4 ,a few missing full stops were inserted1 for example after 8avoided0 on page #di4 ,the transcriber produced the cover image and hereby assigns it to the public domain4 ,ditto marks have been removed and replaced by repetitions of the referenced text4 ,subscripts are indicated by a low line followed by curly brackets1 for example as in ,k#b;,cr#b,o#g4 ,superscripts look like this3 8,,benj,n404 ,original page images are available from archive4org--search for 8photolithography#jj;frit04 ,there are twenty-four advertisements at the end of the book4 ,a new heading is added at the beginning of that section4 ,the original book had the advantages of typography1 page-breaks1 and illustrations to distinguish one ad from the next4 ,in this text edition1 lacking those advantages1 each ad is enclosed within transcriber's markup 8advertisement0 and 8_/advertisement04 ,page #b4 8thought than an ,english translation0 to 8thought that an ,english translation04 ,page #ch4 ,in the sentence 8,if the desired blackening is not effected with one application the operation must be completed01 it seems likely that 8completed0 should be 8repeated04 ,page #ci4 8,gum arabic #ag4e0 to 8,gum arabic #age04 ,page #ec4 8procesess0 to 8processes04 ,page #ef4 8tranfers0 to 8transfers04 ,page #fa4 8,c#f;,h#c7;,,ch#c7c0 to 8,c#f;,h#c7;,,ch#c7c04 ,page #fi4 8great intensity on the sensitive will0 to 8great intensity on the sensitive plate will04 ,page #gc4 8 to #a mm4 7 #a_/ab-a_/beth inch70 to 8 to #a mm4 7 #a_/ej-a_/beth inch701 though other interpretations are possible4 ,for example1 the similar instance on page #he 8#ej-hj cm4 7 #bd to #cf ins470 is wrong 7or1 speaking more charitably1 inaccurate71 but is retained as printed4 ,page #ha4 8transfering0 to 8transferring04