,this text uses utf-#h 7unicode7 file encoding4 ,if the apostrophes and quotation marks in this paragraph appear as garbage1 make sure your text reader's character set or file encoding is set to ,unicode 7,,utf-#h74 ,you may also need to change the default font4 ,as a last resort1 use the ascii-#g version of the file instead4 ,the ,table of ,contents1 ,index1 and all cross-references use paragraph numbers1 shown in 7parentheses74 ,braces have been added to a few long fractions that were originally printed on two lines4 ,the numbers in expressions such as ,r#b1 ,r#c1 ,r#d were printed as superscripts4 ,illustration3 ,a ,,balanced ,,color ,,sphere ,,pastel ,,sketch ,a ,,color ,,notation ,by ,a4 ,h4 ,,munsell ,a ,,measured ,,color ,,system1 ,,based ,,on ,,the ,,three ,,qualities ,hue1 ,value1 and ,chroma with ,illustrative ,models1 ,charts1 and a ,course of ,study ,arranged for ,teachers #bnd ,edition ,revised ,enlarged ,,geo4 ,h4 ,,ellis ,,co4 ,,boston #aijg ,,copyright1 #aije by ,a4 ,h4 ,,munsell ,all rights reserved ,,entered ,,at ,,stationers' ,,hall ,,author',s ,,preface4 ,at various times during the past ten years1 the gist of these pages has been given in the form of lectures to students of the ,normal ,art ,school1 the ,art ,teachers' ,association1 and the ,twentieth ,century ,club4 ,in ,october of last year it was presented before the ,society of ,arts of the ,massachusetts ,institute of ,technology1 at the suggestion of ,professor ,charles ,r4 ,cross4 ,grateful acknowledgment is due to many whose helpful criticism has aided in its development1 notably ,mr4 ,benjamin ,ives ,gilman1 ,secretary of the ,museum of ,fine ,arts1 ,professor ,harry ,e4 ,clifford1 of the ,institute1 and ,mr4 ,myron ,t4 ,pritchard1 master of the ,everett ,school1 ,boston4 ,a4 ,h4 ,m4 ,,chestnut ,,hill1 ,,mass41 #aije4 ,,preface ,,to ,,second ,,edition4 ,the new illustrations in this edition are facsimiles of children's studies with measured color1 made under ordinary school-room conditions4 ,notes and appendices are introduced to meet the questions most frequently asked1 stress being laid on the unbalanced nature of colors usually given to beginners1 and the mischief done by teaching that red1 yellow1 and blue are primary hues4 ,the need of a scientific basis for color values is also emphasized1 believing this to be essential in the discipline of the color sense4 ,a4 ,h4 ,m4 ,,chestnut ,,hill1 ,,mass41 #aijg4 ,,introduction4 ,the lack of definiteness which is at present so general in color nomenclature1 is due in large measure to the failure to appreciate the fundamental characteristics on which color differences depend4 ,for the physicist1 the expression of the wave length of any particular light is in most cases sufficient1 but in the great majority of instances where colors are referred to1 something more than this and something easier of realization is essential4 ,the attempt to express color relations by using merely two dimensions1 or two definite characteristics1 can never lead to a successful system4 ,for this reason alone the system proposed by ,mr4 ,munsell1 with its three dimensions of hue1 value1 and chroma1 is a decided step in advance over any previous proposition4 ,by means of these three dimensions it is possible to completely express any particular color1 and to differentiate it from colors ordinarily classed as of the same general character4 ,the expression of the essential characteristics of a color is1 however1 not all that is necessary4 ,there must be some accurate and not too complicated system for duplicating these characteristics1 one which shall not alter with time or place1 and which shall be susceptible of easy and accurate redetermination4 ,from the teaching standpoint also a logical and sequential development is absolutely essential4 ,this ,mr4 ,munsell seems to have most successfully accomplished4 ,in the determination of his relationships he has made use of distinctly scientific methods1 and there seems no reason why his suggestions should not lead to an exact and definite system of color essentials4 ,the ,munsell photometer1 which is briefly referred to1 is an instrument of wide range1 high precision1 and great sensitiveness1 and permits the valuations which are necessary in his system to be accurately made4 ,we all appreciate the necessity for some improvement in our ideas of color1 and the natural inference is that the training should be begun in early youth4 ,the present system in its modified form possesses elements of simplicity and attractiveness which should appeal to children1 and give them almost unconsciously a power of discrimination which would prove of immense value in later life4 ,the possibilities in this system are very great1 and it has been a privilege to be allowed during the past few years to keep in touch with its development4 ,i cannot but feel that we have here not only a rational color nomenclature1 but also a system of scientific importance and of practical value4 ,h4 ,e4 ,,clifford4 ,,massachusetts ,,institute ,,of ,,technology1 ,february1 #aije4 ,,contents4 ,introduction ,by ,professor ,clifford4 ,part ,i4 ,chapter ,paragraph ,i4 ,,color ,,names3 ,red1 ,yellow1 ,green1 ,blue1 ,purple #a ,appendix ,i4--,misnomers for ,color4 ,,ii4 ,,color ,,qualities3 ,hue1 ,value1 ,chroma #bj ,appendix ,,ii4--,scales of ,hue1 ,value1 and ,chroma4 ,,iii4 ,,color ,,mixture3 ,a ,tri-,dimensional ,balance #ed ,appendix ,,iii4--,false ,color ,balance4 ,,iv4 ,,prismatic ,,colors #hg ,appendix ,,iv4--,children's ,color ,studies4 ,v4 ,,the ,,pigment ,,color ,,sphere3 ,,true ,,color ,,balance #ajb ,appendix ,v4--,schemes based on ,brewster's ,theory4 ,,vi4 ,,color ,,notation3 ,a ,written ,color ,system #acb ,,vii4 ,,color ,,harmony3 ,a ,measured ,relation #adf ,part ,,ii4 ,a ,,color ,,system ,,and ,,course ,,of ,,study ,,based ,,on ,,the ,,color ,,solid ,,and ,,its ,,charts4 ,arranged for nine years of school life4 ,,glossary ,,of ,,color ,,terms4 ,taken from the ,century ,dictionary4 ,,index 7by paragraphs74 ,,chapter ,i4 ,,color ,,names4 ,writing from ,samoa to ,sidney ,colvin in ,london1 ,stevenson#a says3 ,perhaps in the same way it might amuse you to send us any pattern of wall paper that might strike you as cheap1 pretty1 and suitable for a room in a hot and extremely bright climate4 ,it should be borne in mind that our climate can be extremely dark1 too4 ,our sitting-room is to be in varnished wood4 ,the room ,i have particularly in mind is a sort of bed and sitting room1 pretty large1 lit on three sides1 and the colour in favour of its proprietor at present is a topazy yellow4 ,but then with what colour to relieve it8 ,for a little work-room of my own at the back ,i should rather like to see some patterns of unglossy--well1 ,i'll be hanged if ,i can describe this red4 ,it's not ,turkish1 and it's not ,roman1 and it's not ,indian2 but it seems to partake of the last two1 and yet it can't be either of them1 because it ought to be able to go with vermilion4 ,ah1 what a tangled web we weave6 ,anyway1 with what brains you have left choose me and send me some--many--patterns of the exact shade4 ,footnote #a3 ,vailima ,letters1 ,oct4 #h1 #aijb4 7#a7 ,where could be found a more delightful cry for some rational way to describe color8 ,he wants a topazy yellow and a red that is not ,turkish nor ,roman nor ,indian1 but that seems to partake of the last two1 and yet it can't be either of them4 ,as a cap to the climax comes his demand for patterns of the exact shade4 ,thus one of the clearest and most forceful writers of ,english finds himself unable to describe the color he wants4 ,and why8 ,simply because popular language does not clearly state a single one of the three qualities united in every color1 and which must be known before one may even hope to convey his color conceptions to another4 7#b7 ,the incongruous and bizarre nature of our present color names must appear to any thoughtful person4 ,baby blue1 peacock blue1 ,nile green1 apple green1 lemon yellow1 straw yellow1 rose pink1 heliotrope1 royal purple1 ,magenta1 ,solferino1 plum1 and automobile are popular terms1 conveying different ideas to different persons and utterly failing to define colors4 ,the terms used for a single hue1 such as pea green1 sea green1 olive green1 grass green1 sage green1 evergreen1 invisible green1 are not to be trusted in ordering a piece of cloth4 ,they invite mistakes and disappointment4 ,not only are they inaccurate3 they are inappropriate4 ,can we imagine musical tones called lark1 canary1 cockatoo1 crow1 cat1 dog1 or mouse1 because they bear some distant resemblance to the cries of those animals8 ,see paragraph #aca4 ,color needs a system4 7#c7 ,music is equipped with a system by which it defines each sound in terms of its pitch1 intensify1 and duration1 without dragging in loose allusions to the endlessly varying sounds of nature4 ,so should color be supplied with an appropriate system1 based on the hue1 value1 and chroma#b of our sensations1 and not attempting to describe them by the indefinite and varying colors of natural objects4 ,the system now to be considered portrays the three dimensions of color1 and measures each by an appropriate scale4 ,it does not rest upon the whim of an individual1 but upon physical measurements made possible by special color apparatus4 ,the results may be tested by any one who comes to the problem with a clear mind1 a good eye1 and a fair supply of patience4 ,footnote #b3 ,see color variables in ,glossary4 ,clear mental images make clear speech4 ,vague thoughts find vague utterance4 7#d7 ,the child gathers flowers1 hoards colored beads1 chases butterflies1 and begs for the gaudiest painted toys4 ,at first his strong color sensations are sufficiently described by the simple terms of red1 yellow1 green1 blue1 and purple4 ,but he soon sees that some are light1 while others are dark1 and later comes to perceive that each hue has many grayer degrees4 ,now1 if he wants to describe a particular red1--such as that of his faded cap1--he is not content to merely call it red1 since he is aware of other red objects which are very unlike it4 ,so he gropes for means to define this particular red2 and1 having no standard of comparison1--no scale by which to estimate1--he hesitatingly says it is a sort of dull red4 7#e7 ,thus early is he cramped by the poverty of color language4 ,he has never been given an appropriate word for this color quality1 and has to borrow one signifying the opposite of sharp1 which belongs to edge tools rather than to colors4 ,most color terms are borrowed from other senses4 7#f7 ,when his older sister refers to the tone of her green dress1 or speaks of the key of color in a picture1 he is naturally confused1 because tone and key are terms associated in his mind with music4 ,it may not be long before he will hear that a color note has been pitched too high1 or that a certain artist paints in a minor key4 ,all these terms lead to mixed and indefinite ideas1 and leave him unequipped for the clear expression of color qualities4 7#g7 ,musical art is not so handicapped4 ,it has an established scale with measured intervals and definite terms4 ,likewise1 coloristic art must establish a scale1 measure its intervals1 and name its qualities in unmistakable fashion4 ,color has three dimensions4 7#h7 ,it may sound strange to say that color has three dimensions1 but it is easily proved by the fact that each of them can be measured4 ,thus in the case of the boy's faded cap its redness or ,,hue#c is determined by one instrument2 the amount of light in the red1 which is its ,,value1#c is found by another instrument2 while still a third instrument determines the purity or ,,chroma#c of the red4 ,the omission of any one of these three qualities leaves us in doubt as to the character of a color1 just as truly as the character of this studio would remain undefined if the length were omitted and we described it as #bb feet wide by #ad feet high4 ,the imagination would be free to ascribe any length it chose1 from #be to #ajj feet4 ,this length might be differently conceived by every individual who tried to supply the missing factor4 7#i7 ,to illustrate the tri-dimensional nature of colors4 ,suppose we peel an orange and divide it in five parts1 leaving the sections slightly connected below 7,fig4 #d74 ,then let us say that all the reds we have ever seen are gathered in one of the sections1 all yellows in another1 all greens in the third1 blues in the fourth1 and purples in the fifth4 ,next we will assort these ,,hues in each section so that the lightest are near the top1 and grade regularly to the darkest near the bottom4 ,a white wafer connects all the sections at the top1 and a black wafer may be added beneath4 ,see ,plate ,i4 ,illustration3 ,fig4 #d4 ,footnote #c3 ,for definitions of ,hue1 ,value1 and ,chroma1 see paragraphs #bj-bc4 7#aj7 ,the fruit is then filled with assorted colors1 graded from white to black1 according to their ,,values1 and disposed by their ,,hues in the five sections4 ,a slice near the top will uncover light values in all hues1 and a slice near the bottom will find dark values in the same hues4 ,a slice across the middle discloses a circuit of hues all of ,,middle ,,value2 that is1 midway between the extremes of white and black4 7#aa7 ,two color dimensions are thus shown in the orange1 and it remains to exhibit the third1 which is called ,,chroma1 or strength of color4 ,to do this1 we have only to take each section in turn1 and1 without disturbing the values already assorted1 shove the grayest in toward the narrow edge1 and grade outward to the purest on the surface4 ,each slice across the fruit still shows the circuit of hues in one uniform value2 but the strong chromas are at the outside1 while grayer and grayer chromas make a gradation inward to neutral gray at the centre1 where all trace of color disappears4 ,the thin edges of all sections unite in a scale of gray from black to white1 no matter what hue each contains4 ,the curved outside of each section shows its particular hue graded from black to white2 and1 should the section be cut at right angles to the thin edge1 it would show the third dimension1--chroma1--for the color is graded evenly from the surface to neutral gray4 ,a pin stuck in at any point traces the third dimension4 ,illustration3 ,fig4 #e4 ,a color sphere can be used to unite the three dimensions of hue1 value1 and chroma4 7#ab7 ,having used the familiar structure of the orange as a help in classifying colors1 let us substitute a geometric solid1 like a sphere1#d and make use of geographical terms4 ,the north pole is white4 ,the south pole is black4 ,the equator is a circuit of middle reds1 yellows1 greens1 blues1 and purples4 ,parallels above the equator describe this circuit in lighter values1 and parallels below trace it in darker values4 ,the vertical axis joining black and white is a neutral scale of gray values1 while perpendiculars to it 7like a pin thrust into the orange7 are scales of chroma4 ,thus our color notions may be brought into an orderly relation by the color sphere4 ,any color describes its light and strength by its location in the solid or on the surface1 and is named by its place in the combined scales of hue1 value1 and chroma4 ,footnote #d3 ,see frontispiece4 ,two dimensions fail to describe a color4 7#ac7 ,much of the popular misunderstanding of color is caused by ignorance of these three dimensions or by an attempt to make two dimensions do the work of three4 7#ad7 ,flat diagrams showing hues and values1 but omitting to define chromas1 are as incomplete as would be a map of ,switzerland with the mountains left out1 or a harbor chart without indications of the depth of water4 ,we find by aid of the measuring instruments that pigments are very unequal in this third dimension1--chroma1--producing mountains and valleys on the color sphere1 so that1 when the color system is worked out in pigments and charted1 some colors must be traced well out beyond the spherical surface 7paragraphs #abe-abg74 ,indeed1 a ,,color ,,tree#e is needed to display by the unequal levels and lengths of its branches the individuality of pigment colors4 ,but1 whatever solid or figure is used to illustrate color relations1 it must combine the three scales of hue1 value1 and chroma1 and these definite scales furnish a name for every color based upon its intrinsic qualities1 and free from terms purloined in other sensations1 or caught from the fluctuating colors of natural objects4 ,footnote #e3 ,for description of the ,color ,tree see paragraphs #cc and #cd4 ,how this system describes the spectrum4 7#ae7 ,the solar spectrum and rainbow are the most stimulating color experiences with which we are acquainted4 ,can they be described by this solid system8 7#af7 ,the lightest part of the spectrum is a narrow field of greenish yellow1 grading into darker red on one side and into darker green upon the other1 followed by still darker blue and purple4 ,upon the sphere the values of these spectral colors trace a path high up on the yellow section1 near white1 and slanting downward across the red and green sections1 which are traversed near the level of the equator1 it goes on to cross the blue and purple well down toward black4 7#ag7 ,this forms an inclined circuit1 crossing the equator at opposite points1 and suggests the ecliptic or the rings of ,saturn 7see outside cover74 ,a pale rainbow would describe a slanting circuit nearer white1 and a dimmer one would fall within the sphere1 while an intensely brilliant spectrum projects far beyond the surface of the sphere1 so greatly is the chroma of its hues in excess of the common pigments with which we work out our problems4 7#ah7 ,at the outset it is well to recognize the place of the spectrum in this system1 not only because it is the established basis of scientific study1 but especially because the invariable order assumed by its hues is the only stable hint which ,nature affords us in her infinite color play4 7#ai7 ,all our color sensations are included in the color solid4 ,none are left out by its scales of hue1 value1 and chroma4 ,indeed1 the imagination is led to conceive and locate still purer colors than any we now possess4 ,such increased degrees of color sensation can be named1 and clearly conveyed by symbols to another person as soon as the system is comprehended4 ,,appendix ,,to ,,chapter ,i4 ,misnomers for ,color4 ,the ,century ,dictionary helps an intelligent study of color by its clear definitions and cross-references to ,,hue1 ,,value1 and ,,chroma1--leaving no excuse for those who would confuse these three qualities or treat a degree of any quality as the quality itself4 ,obscure statements were frequent in text-books before these new definitions appeared4 ,thus the term shade should be applied only to darkened values1 and not to hues or chromas4 ,yet one writer says1 ,this yellow shades into green1 which is certainly a change of hue1 and then speaks of a brighter shade in spite of his evident intention to suggest a stronger chroma1 which is neither a shade nor brighter luminosity4 ,children gain wrong notions of tint and shade from the so-called standard colors shown to them1 which present tints of red and blue much darker than the shades of yellow4 ,this is bewildering1 and1 like their elders1 they soon drop into the loose habit of calling any degree of color-strength or color-light a shade4 ,value is a better term to describe the light which color reflects to the eye1 and all color values1 light or dark1 are measured by the value-scale4 ,tone is used in a confusing way to mean different things4 ,thus in the same sentence we see it refers to a single touch of the brush1--which is not a tone1 but a paint spot1--and then we read that the tone of the canvas is golden4 ,this cannot mean that each paint spot is the color of gold1 but is intended to suggest that the various objects depicted seem enveloped in a yellow atmosphere4 ,tone is1 in fact1 a musical term appropriate to sound1 but out of place in color4 ,it seems better to call the brush touch a color-spot3 then the result of an harmonious relation between all the spots is color-envelope1 or1 as in ,rood1 the chromatic composition4 ,intensity is a misleading term1 if chroma be intended1 for it depends on the relative light of spectral hues4 ,it is a degree rather than a quality1 as appears in the expressions1 intense heat1 light1 sound1--intensity of stimulus and reaction4 ,being a degree of many qualities1 it should not be used to describe the quality itself4 ,the word becomes especially unfit when used to describe two very different phases of a color1--as its intense illumination1 where the chroma is greatly weakened1 and the strongest chroma which is found in a much lower value4 ,purity is also to be avoided in speaking of pigments1 for not one of our pigments represents a single pure ray of the spectrum4 ,examples are constantly found of the mental blur caused by such unfortunate terms1 and1 since misunderstanding becomes impossible with measured degrees of hue1 value1 and chroma1 it seems only a question of time when they will take the place of tint1 tone1 shade1 purity and intensity4 ,,chapter ,,ii4 ,,color ,,qualities4 7#bj7 ,the three color qualities are hue1 value1 and chroma4 ,,hue is the name of a color4 7#ba7 ,hue is the quality by which we distinguish one color from another1 as a red from a yellow1 a green1 a blue1 or a purple4 ,this names the hue1 but does not tell whether it is light or dark1 weak or strong1--leaving us in doubt as to its value and its chroma4 ,science attributes this quality to difference in the ,,length of ether waves impinging on the retina1 which causes the sensation of color4 ,the wave length ,m4 #ebfi gives a sensation of green1 while ,m4 #fhfg gives a sensation of red4#f ,footnote #f3 ,see ,glossary for definitions of ,micron1 ,photometer1 ,retina1 and ,red1 also for ,hue1 ,tint1 ,shade1 ,value1 ,color ,variables1 ,luminosity1 and ,chroma4 ,,value is the light of a color4 7#bb7 ,value is the quality by which we distinguish a light color from a dark one4 ,color values are loosely called tints and shades1 but the terms are frequently misapplied4 ,a tint should be a light value1 and a shade should be darker2 but the word shade has become a general term for any sort of color1 so that a shade of yellow may prove to be lighter than a tint of blue4 ,a photometric#g scale of value places all colors in relation to the extremes of white and black1 but cannot describe their hue or their chroma4 ,science describes this quality as due to difference in the ,,height or amplitude of ether waves impinging on the retina4 ,small amplitudes of the wave lengths given in paragraph #ba produce the sensation of dark green and dark red3 larger amplitudes give the sensation of lighter green and lighter red4 ,footnote #g3 ,see ,photometer in paragraph #fe4 ,,chroma is the strength of a color4 7#bc7 ,chroma is the quality by which we distinguish a strong color from a weak one4 ,to say that a rug is strong in color gives no hint of its hues or values1 only its chromas4 ,loss of chroma is loosely called fading1 but this word is frequently used to include changes of value and hue4 ,take two autumn leaves1 identical in color1 and expose one to the weather1 while the other is waxed and pressed in a book4 ,soon the exposed leaf fades into a neutral gray1 while the protected one preserves its strong chroma almost intact4 ,if1 in fading1 the leaf does not change its hue or its value1 there is only a loss of chroma1 but the fading process is more likely to induce some change of the other two qualities4 ,fading1 however1 cannot define these changes4 ,science describes chroma as the purity of one wave length separated from all others4 ,other wave lengths1 ,,intermingling1 make its chroma less pure4 ,a beam of daylight can combine all wave lengths in such balance as to give the sensation of whiteness1 because no single wave is in excess4#h ,footnote #h3 ,see definition of ,white in ,glossary4 7#bd7 ,the color sphere 7see ,fig4 #a7 is a convenient model to illustrate these three qualities1--hue1 value1 and chroma1--and unite them by measured scales4 7#be7 ,the north pole of the color sphere is white1 and the south pole black4 ,value or luminosity of colors ranges between these two extremes4 ,this is the vertical scale1 to be memorized as ,v1 the initial for both value and vertical4 ,vertical movement through color may thus be thought of as a change of value1 but not as a change of hue or of chroma4 ,hues of color are spread around the equator of the sphere4 ,this is a horizontal scale1 memorized as ,h1 the initial for both hue and horizontal4 ,horizontal movement around the color solid is thus thought of as a change of hue1 but not of value or of chroma4 ,a line inward from the strong surface hues to the neutral gray axis1 traces the graying of each color1 which is loss of chroma1 and conversely a line beginning with neutral gray at the vertical axis1 and becoming more and more colored until it passes outside the sphere1 is a scale of chroma1 which is memorized as ,c1 the initial both for chroma and centre4 ,thus the sphere lends its three dimensions to color description1 and a color applied anywhere within1 without1 or on its surface is located and named by its degree of hue1 of value1 and of chroma4 ,illustration3 ,fig4 #a4 ,,hues first appeal to the child1 ,,values next1 and ,,chromas last4 7#bf7 ,color education begins with ability to recognize and name certain hues1 such as red1 yellow1 green1 blue1 and purple 7see paragraphs #ahb and #ahc74 ,nature presents these hues in union with such varieties of value and chroma that1 unless there be some standard of comparison1 it is impossible for one person to describe them intelligently to another4 7#bg7 ,the solar spectrum forms a basis for scientific color analysis1 taught in technical schools2 but it is quite beyond the comprehension of a child4 ,he needs something more tangible and constantly in view to train his color notions4 ,he needs to handle colors1 place them side by side for comparison1 imitate them with crayons1 paints1 and colored stuffs1 so as to test the growth of perception1 and learn by simple yet accurate terms to describe each by its hue1 its value1 and its chroma4 7#bh7 ,pigments1 rather than the solar spectrum1 are the practical agents of color work4 ,certain of them1 selected and measured by this system 7see ,chapter ,v471 will be known as ,,middle ,,colors1 because they stand midway in the scales of value and chroma4 ,these middle colors are preserved in imperishable enamels1#i so that the child may handle and fix them in his memory1 and thus gain a permanent basis for comparing all degrees of color4 ,he learns to grade each middle color to its extremes of value and chroma4 ,footnote #i3 ,when recognized for the first time1 a middle green1 blue1 or purple1 is accepted by most persons as well within their color habit1 but middle red and middle yellow cause somewhat of a shock4 ,that isn't red1 they say1 it's terra cotta4 ,yellow8 ,oh1 no1 that's--well1 it's a very peculiar shade4 ,yet these are as surely the middle degrees of red and yellow as are the more familiar degrees of green1 blue1 and purple4 ,this becomes evident as soon as one accepts physical tests of color in place of personal whim4 ,it also opens the mind to a generally ignored fact1 that middle reds and yellows1 instead of the screaming red and yellow first given a child1 are constantly found in examples of rich and beautiful color1 such as ,persian rugs1 ,japanese prints1 and the masterpieces of painting4 7#bi7 ,experiments with crayons and paints1 and efforts to match middle colors1 train his color sense to finer perceptions4 ,having learned to name colors1 he compares them with the enamels of middle value1 and can describe how light or dark they are4 ,later he perceives their differences of strength1 and1 comparing them with the enamels of middle chroma1 can describe how weak or strong they are4 ,thus the full significance of these middle colors as a practical basis for all color estimates becomes apparent2 and1 when at a more advanced stage he studies the best examples of decorative color1 he will again encounter them in the most beautiful products of ,oriental art4 ,is it possible to define the endless varieties of color8 7#cj7 ,at first glance it would seem almost hopeless to attempt the naming of every kind and degree of color4 ,but1 if all these varieties possess the same three qualities1 only in different degrees1 and if each quality can be measured by a scale1 then there is a clue to this labyrinth4 ,a ,,color ,,sphere and ,,color ,,tree to unite hue1 value1 and chroma4 7#ca7 ,this clue is found in the union of these three qualities by measured scales in a color sphere and color tree4#aj ,the equator of the sphere#aa may be divided into ten parts1 and serve as the scale of hue1 marked ,r1 ,,yr1 ,y1 ,,gy1 ,g1 ,,bg1 ,b1 ,,pb1 ,p1 and ,,rp4 ,its vertical axis may be divided into ten parts to serve as the scale of value1 numbered from black 7#j7 to white 7#aj74 ,any perpendicular to the neutral axis is a scale of chroma4 ,on the plane of the equator this scale is numbered #a1 #b1 #c1 #d1 #e1 from the centre to the surface4 ,illustration3 ,fig4 #c4 ,footnote #aj3 ,see ,color ,tree in paragraph #ad4 ,footnote #aa3 ,unaware that the spherical arrangement had been used years before1 ,i devised a double tetrahedron to classify colors1 while a student of painting in #ahgi4 ,it now appears that the sphere was common property with psychologists1 having been described by ,runge in #ahaj4 ,earlier still1 ,lambert had suggested a pyramidal form4 ,both are based on the erroneous assumption that red1 yellow1 and blue are primary sensations1 and also fail to place these hues in a just scale of luminosity4 ,my twirling color solid and its completer development in the present model have always made prominent the artistic feeling for color value4 ,it differs in this and in other ways from previous systems1 and is fortunate in possessing new apparatus to measure the degree of hue1 value1 and chroma4 7#cb7 ,this chroma scale may be raised or lowered to any level of value1 always remaining perpendicular to the axis1 and serving to measure the chroma of every hue at every level of value4 ,the fact that some colors exceed others to such an extent as to carry them out beyond the sphere is proved by measuring instruments1 but the fact is a new one to many persons4 7,figs4 #b and #c47 ,illustration3 ,fig4 #b4 7,see ,fig4 #bj7 ,the ,color ,tree 7#cc7 ,for this reason the ,,color ,,tree is a completer model than the sphere1 although the simplicity of the latter makes it best for a child's comprehension4 7#cd7 ,the color tree is made by taking the vertical axis of the sphere1 which carries a scale of value1 for the trunk4 ,the branches are at right angles to the trunk2 and1 as in the sphere1 they carry the scale of chroma4 ,colored balls on the branches tell their ,hue4 ,in order to show the ,,maxima of color1 each branch is attached to the trunk 7or neutral axis7 at a level demanded by its value1--the yellow nearest white at the top1 then the green1 red1 blue1 and purple branches1 approaching black in the order of their lower values4 ,it will be remembered that the chroma of the sphere ceased with #e at the equator4 ,the color tree prolongs this through #f1 #g1 #h1 and #i4 ,the branch ends carry colored balls1 representing the most powerful red1 yellow1 green1 blue1 and purple pigments which we now possess1 and could be lengthened1 should stronger chromas be discovered4#ab ,footnote #ab3 ,see ,plate ,i4 7#ce7 ,such models set up a permanent image of color relations4 ,every point is self-described by its place in the united scales of hue1 value1 and chroma4 ,these scales fix each new perception of color in the child's mind by its situation in the color solid4 ,the importance of such a definite image can hardly be overestimated1 for without it one color sensation tends to efface another4 ,when the child looks at a color1 and has no basis of comparison1 it soon leaves a vague memory that cannot be described4 ,these models1 on the contrary1 lead to an intelligent estimate of each color in terms of its hue1 its value1 and its chroma2 while the permanent enamels correct any personal bias by a definite standard4 7#cf7 ,thus defined1 a color falls into logical relation with all other colors in the system1 and is easily memorized1 so that its image may be recalled at any distance of time or place by the notation4 7#cg7 ,these solid models help to memorize and assemble colors and the memory is further strengthened by a simple ,,notation1 which records each color so that it cannot be mistaken for any other4 ,by these written scales a child gains an instinctive estimate of relations1 so that1 when he is delighted with a new color combination1 its proportions are noted and understood4 7#ch7 ,musical art has long enjoyed the advantages of a definite scale and notation4 ,should not the art of coloring gain by similar definition8 ,the musical scale is not left to personal whim1 nor does it change from day to day2 and something as clear and stable would be an advantage in training the color sense4 7#ci7 ,perception of color is crude at first4 ,the child sees only the most obvious distinctions1 and prefers the strongest stimulation4 ,but perception soon becomes refined by exercise1 and1 when a child tries to imitate the subtle colors of nature with paints1 he begins to realize that the strongest colors are not the most beautiful1--rather the tempered ones1 which may be compared to the moderate sounds in music4 ,to describe these tempered colors1 he must estimate their hue1 value1 and chroma1 and be able to describe in what degree his copy departs from the natural color4 ,and1 with this gain in perception and imitation of natural color1 he finds a strong desire to invent combinations to please his fancy4 ,thus the study divides into three related attitudes1 which may be called recognition1 imitation1 and invention4 ,recognition of color is fundamental1 but it would be tedious to spend a year or two in formal and dry exercises to train recognition of color alone2 for each step in recognition of color is best tested by exercise in its imitation and arrangement4 ,when perception becomes keener1 emphasis can be placed on imitation of the colors found in art and in nature1 resting finally on the selection and grouping of colors for design4#ac ,footnote #ac3 ,see ,course of ,study1 ,part ,,ii4 ,every color can be recognized1 named1 matched1 imitated1 and written by its ,,hue1 ,,value1 and ,,chroma4 7#dj7 ,the notation used in this system places ,hue 7expressed by an initial7 at the left2 ,value 7expressed by a number7 at the right and above a line2 and ,chroma 7also expressed by a number7 at the right1 below the line4 ,thus ,r #e_/i means ,,hue 7red71 ,,value 7#e7_/;,,chroma 7#i71 and will be found to represent the qualities of the pigment vermilion4#ad ,footnote #ad3 ,see ,chapter ,,vi4 ,hue1 value1 and chroma unite in every color sensation1 but the child cannot grasp them all at once4 ,hue-difference appeals to him first1 and he gains a permanent idea of five principal hues from the enamels of ,,middle ,,colors1 learning to name1 match1 imitate1 and finally write them by their initials3 ,r 7red71 ,y 7yellow71 ,g 7green71 ,b 7blue71 and ,p 7purple74 ,intermediates formed by uniting successive pairs are also written by the joined initials1 ,,yr 7yellow-red71 ,,gy 7green-yellow71 ,,bg 7blue-green71 ,,pb 7purple-blue71 and ,,rp 7red-purple74 7#da7 ,ten differences of hue are as many as a child can render at the outset1 yet in matching and imitating them he becomes aware of their light and dark quality1 and learns to separate it from hue as value-difference4 ,middle colors1 as implied by that name1 stand midway between white and black1--that is1 on the equator of the sphere1--so that a middle red will be written ,r #e_/1 suggesting the steps #f1 #g1 #h1 and #i which are above the equator1 while steps #d1 #c1 #b1 and #a are below4 ,it is well to show only three values of a color at first2 for instance1 the middle value contrasted with a light and a dark one4 ,these are written ,r #c_/1 ,r #e_/1 ,r #g_/4 ,soon he perceives and can imitate finer differences1 and the red scale may be written entire1 as ,r #a_/1 ,r #b_/1 ,r #c_/1 ,r #d_/1 ,r #e_/1 ,r #f_/1 ,r #g_/1 ,r #h_/1 ,r #i_/1 with black as #j and white as #aj4 7#db7 ,chroma-difference is the third and most subtle color quality4 ,the child is already unconsciously familiar with the middle chroma of red1 having had the enamels of ,,middle ,,color always in view1 and the red enamel is to be contrasted with the strongest and weakest red chromas obtainable4 ,these he writes ,r _/#a1 ,r _/#e1 ,r _/#i1 seeing that this describes the chromas of red1 but leaves out its values4 ,r #e_/a1 ,r #e_/e1 ,r #e_/i1 is the complete statement1 showing that1 while both hue and value are unchanged1 the chroma passes from grayish red to middle red 7enamel first learned7 and out to the strongest red in the chroma scale obtained by vermilion4 7#dc7 ,it may be long before he can imitate the intervening steps of chroma1 many children finding it difficult to express more than five steps of the chroma scale1 although easily making ten steps of value and from twenty to thirty-five steps of hue4 ,this interesting feature is of psychologic value1 and has been followed in the color tree and color sphere4 ,does such a scientific scheme leave any outlet for feeling and personal expression of beauty8 7#dd7 ,lest this exact attitude in color study should seem inartistic1 compared with the free and almost chaotic methods in use1 let it be said that the stage thus far outlined is frankly disciplinary4 ,it is somewhat dry and unattractive1 just as the early musical training is fatiguing without inventive exercises4 ,the child should be encouraged at each step to exercise his fancy4 7#de7 ,instead of cramping his outlook upon nature1 it widens his grasp of color1 and stores the memory with finer differences1 supplying more material by which to express his sense of coloristic beauty4 7#df7 ,color harmony1 as now treated1 is a purely personal affair1 difficult to refer to any clear principles or definite laws4 ,the very terms by which it seeks expression are borrowed from music1 and suggest vague analogies that fail when put to the test4 ,color needs a new set of expressive terms1 appropriate to its qualities1 before we can make an analysis as to the harmony or discord of our color sensations4 7#dg7 ,this need is supplied in the present system by measured ,,charts1 and a ,,notation4 ,their very construction preserves the balance of colors1 as will be shown in the next chapter1 while the chapter on harmony 7,chapter ,,vii47 shows how harmonious pairs and triads of color may be found by ,,masks with measured intervals4 ,in fact1 practice in the use of the charts supplies the imagination with scales and sequences of color quite as definite and quite as easily written as those sound intervals by which the musician conveys to others his sense of harmony4 ,and1 although in neither art can training alone make the artist1 yet a technical grasp of these formal scales gives acquaintance with the full range of the instrument1 and is indispensable to artistic expression4 ,from these color scales each individual is free to choose combinations in accord with his feeling for color harmony4 ,let us make an outline of the course of color study traced in the preceding pages4#ae ,footnote #ae3 ,see ,part ,,ii41 ,a ,color ,system and ,course of ,study4 ,,perception of color4 7#dh7 ,hue-difference4 ,middle hues 7#e principals74 ,middle hues 7#e intermediates74 ,middle hues 7#aj placed in sequence as ,,scale of ,,hue74 ,value-difference4 ,light1 middle1 and dark values 7without change of hue74 ,light1 middle1 and dark values 7traced with #e principal hues74 #aj values traced with each hue4 ,,scale of ,,value4 ,the ,color ,sphere4 ,chroma-difference4 ,strong1 middle1 and weak chroma 7without change of hue74 ,strong1 middle and weak chroma 7traced with three values without change of hue74 ,strong1 middle1 and weak chroma 7traced with three values and ten hues74 ,maxima of color and their gradation to white1 black1 and gray4 ,the ,color ,tree4 ,,expression of color4 7#di7 ,matching and imitation of hues 7using stuffs1 crayons1 and paints74 ,matching and imitation of values and hues 7using stuffs1 crayons1 and paints74 ,matching and imitation of chromas1 values1 and hues 7using stuffs1 crayons1 and paints74 ,notation of color4 ,value ,v ,hue ------ 1 ,h - 1 ,chroma ,c ,initial for hue1 numeral above for value1 numeral below for chroma4 ,sequences of color4 ,two scales united1 as hue and value1 or chroma and value4 ,three scales united1--each step a change of hue1 value1 and chroma4 ,balance of color4 ,opposites of equal value and chroma 7,r #e_/e and ,,bg #e_/e74 ,opposites of equal value and unequal chroma 7,r #e_/i and ,,bg #e_/c74 ,opposites unequal both in value and chroma 7,r #g_/c and ,,bg #c_/g74 ,,area as an element of balance4 ,,harmony of color4 7#ej7 ,selection of colors that give pleasure4 ,study of butterfly wings and flowers1 recorded by the ,,notation4 ,study of painted ornament1 rugs1 and mosaics1 recorded by the ,,notation4 ,personal choice of color ,,pairs1 balanced by ,h1 ,v1 ,c1 and area4 ,personal choice of color ,,triads1 balanced by ,h1 ,v1 ,c1 and area4 ,grouping of colors to suit some practical use3 wall papers1 rugs1 book covers1 etc4 ,their analysis by the written notation4 ,search for principles of harmony1 expressed in measured terms4 ,a definite plan of color study1 with freedom as to details of presentation4#af ,footnote #af3 ,see ,color ,study assigned to each grade1 in ,part ,,ii4 7#ea7 ,having memorized these broad divisions of the study1 a clever teacher will introduce many a detail1 to meet the mood of the class1 or correlate this subject with other studies1 without for a moment losing the thread of thought or befogging the presentation4 ,but to range at random in the immense field of color sensations1 without plan or definite aim in view1 only courts fatigue of the retina and a chaotic state of mind4 7#eb7 ,the same broad principles which govern the presentation of other ideas apply with equal force in this study4 ,a little1 well apprehended1 is better than a mass of undigested facts4 ,if the child is led to discover1 or at least to think he is discovering1 new things about color1 the mind will be kept alert and seek out novel illustrations at every step4 ,now and then a pupil will be found who leads both teacher and class by intuitive appreciation of color1 and it is a subtle question how far such a nature can be helped or hurt by formal exercises4 ,but such an exception is rare1 and goes to prove that systematic discipline of the color sense is necessary for most children4 7#ec7 ,outdoor nature and indoor surroundings offer endless color illustrations4 ,birds1 flowers1 minerals1 and the objects in daily use take on a new interest when their varied colors are brought into a conscious relation1 and clearly named4 ,a tri-dimensional perception1 like this sense of color1 requires skilful training1 and each lesson must be simplified to the last point practicable4 ,it must not be too long1 and should lead to some definite result which a child can grasp and express with tolerable accuracy1 while its difficulties should be approached by easy stages1 so as to avoid failure or discouragement4 ,the success of the present effort is the best incentive to further achievement4 ,,appendix ,,to ,,chapter ,,ii4 ,,plate ,i4 ,,the ,,color ,,sphere1 ,,with ,,measured ,,scales ,,of ,,hue1 ,,value1 ,,and ,,chroma4 ,the teacher of elementary grades introduces these scales of tempered color as fast as the child's interest is awakened to their need by the exercises shown in ,plates ,,ii4 and ,,iii4 ,thus the ,hue scale is learned before the end of the second year1 the ,value scale during the next two years1 and the ,chroma scale in the fifth year4 ,by the time a child is ten years old these definite color scales have become part of his mental furnishing1 so that he can name1 write1 and memorize any color group4 #a4 ,the ,color ,sphere in ,skeleton4 ,this diagram shows the middle colors on the equator1 with strong red1 yellow1 green1 blue1 and purple1 each at its proper level in the value scale1 and projecting in accordance with its scale of chroma4 ,see the complete description of these scales in ,chapter ,,ii4 #b4 ,the ,color ,score4 ,fifteen typical steps taken from the color sphere are here spread out in a flat field4 ,the ,,five ,,middle ,,colors form the centre level1 with the same hues in a lighter value above and in a darker value below4 ,chapter ,,vi4 describes the making of this ,score1 and its use in analyzing colors and preserving a written record of their groups4 #c4 ,the ,value ,scale and ,chroma ,scale4 ,each of the five color maxima is thus shown at its proper level in the scale of light1 and graded by uniform steps from its strongest chroma inward to neutrality at the axis of the sphere4 ,pigment inequalities here become very apparent4 ,illustration3 ,,plate ,i4 ,copyright #aijg by ,a4 ,h4 ,munsell4 ,,for ,,plates ,,ii4 ,,iii41 ,,see ,,appendix ,,to ,,chapter ,,iv41 ,,children',s ,,color ,,studies4 ,,chapter ,,iii4 ,,color ,,mixture ,,and ,,balance4 ,all colors grasped in the hand4 ,illustration3 ,fig4 #f4 7#ed7 ,let us recall the names and order of colors given in the last chapter1 with their assemblage in a sphere by the three qualities of ,,hue1 ,,value1 and ,,chroma4 ,it will aid the memory to call the thumb of the left hand ,,red1 the forefinger ,,yellow1 the middle finger ,,green1 the ring finger ,,blue1 and the little finger ,,purple 7,fig4 #f74 ,when the finger tips are in a circle1 they represent a circuit of hues1 which has neither beginning nor end1 for we can start with any finger and trace a sequence forward or backward4 ,now close the tips together for white1 and imagine that the five strong hues have slipped down to the knuckles1 where they stand for the equator of the color ,sphere4 ,still lower down at the wrist is black4 7#ee7 ,the hand thus becomes a color holder1 with white at the finger tips1 black at the wrist1 strong colors around the outside1 and weaker colors within the hollow4 ,each finger is a scale of its own color1 with white above and black below1 while the graying of all the hues is traced by imaginary lines which meet in the middle of the hand4 ,thus a child's hand may be his substitute for the color sphere1 and also make him realize that it is filled with grayer degrees of the outside colors1 all of which melt into gray in the centre4 ,neighborly and opposite hues2 and their mixture4 7#ef7 ,let this circle 7,fig4 #g7 stand for the equator of the color sphere with the five principal hues 7written by their initials ,r1 ,y1 ,g1 ,b1 and ,p7 spaced evenly about it4 ,some colors are neighbors1 as red and yellow1 while others are opposites4 ,as soon as a child experiments with paints1 he will notice the different results obtained by mixing them4 ,illustration3 ,fig4 #g4 ,first1 the neighbors1 that is1 any pair which lie next one another1 as red and yellow1 will unite to make a hue which retains a suggestion of both4 ,it is intermediate between red and yellow1 and we call it ,,yellow-,,red4#ag 7#eg7 ,green and yellow unite to form ,,green-,,yellow1 blue and green make ,,blue-,,green1 and so on with each succeeding pair4 ,these intermediates are to be written by their initials1 and inserted in their proper place between the principal hues4 ,it is as if an orange 7paragraph #i7 were split into ten sectors instead of five1 with red1 yellow1 green1 blue1 and purple as alternate sectors1 while half of each adjoining color pair were united to form the sector between them4 ,the original order of five hues is in no wise disturbed1 but linked together by five intermediate steps4 7#eh7 ,here is a table of the intermediates made by mixing each pair3-- ,red and yellow unite to form yellow-red 7,,yr71 popularly called orange4#ag ,yellow and green unite to form green-yellow 7,,gy71 popularly called grass green4 ,green and blue unite to form blue-green 7,,bg71 popularly called peacock blue4 ,blue and purple unite to form purple-blue 7,,pb71 popularly called violet4 ,purple and red unite to form red-purple 7,,rp71 popularly called plum4 ,using the left hand again to hold colors1 the principal hues remain unchanged on the knuckles1 but in the hollows between them are placed intermediate hues1 so that the circle now reads3 red1 yellow-red1 yellow1 green-yellow1 green1 blue-green1 blue1 purple-blue1 purple1 and red-purple1 back to the red with which we started4 ,this circuit is easily memorized1 so that the child may begin with any color point1 and repeat the series clock wise 7that is1 from left to right7 or in reverse order4 ,footnote #ag3 ,orange is a variable union of yellow and red4 ,see ,appendix4 7#ei7 ,each principal hue has thus made two close neighbors by mixing with the nearest principal hue on either hand4 ,the neighbors of red are a yellow-red on one side and a purple-red on the other4 ,the neighbors of green are a green-yellow on one hand and a blue-green on the other4 ,it is evident that a still closer neighbor could be made by again mixing each consecutive pair in this circle of ten hues2 and1 if the process were continued long enough1 the color steps would become so fine that the eye could see only a circuit of hues melting imperceptibly one into another4 7#fj7 ,but it is better for the child to gain a fixed idea of red1 yellow1 green1 blue1 and purple1 with their intermediates1 before attempting to mix pigments1 and these ten steps are sufficient for primary education4 7#fa7 ,next comes the question of opposites in this circle4 ,a line drawn from red1 through the centre1 finds its opposite1 blue-green4#ah ,if these colors are mixed1 they unite to form gray4 ,indeed1 the centre of the circle stands for a middle gray1 not only because it is the centre of the neutral axis between black and white1 but also because any pair of opposites will unite to form gray4 ,footnote #ah3 ,green is often wrongly assigned as the opposite of red4 ,see ,appendix1 on ,false ,color ,balance4 7#fb7 ,this is a table of five mixtures which make neutral gray3 ,red ,blue-green ,yellow ,purple-blue ,opposites ,green ,red-purple ,each pair of which unites ,blue ,yellow-red in neutral gray4 ,purple ,green-yellow 7#fc7 ,but if1 instead of mixing these opposite hues1 we place them side by side1 the eye is so stimulated by their difference that each seems to gain in strength2 i4e41 each enhances the other when separate1 but destroys the other when mixed4 ,this is a very interesting point to be more fully illustrated by the help of a color wheel in ,chapter ,v41 paragraph #ajf4 ,what we need to remember is that the mixture of neighborly hues makes them less stimulating to the eye1 because they resemble each other1 while a mixture of opposite hues extinguishes both in a neutral gray4 ,hues once removed1 and their mixture4 ,illustration3 ,fig4 #h4 7#fd7 ,there remains the question1 ,what will happen if we mix1 not two neighbors1 nor two opposites1 but a pair of hues once removed in the circle1 such as red and green8 ,a line joining this pair does not pass through the neutral centre1 but to one side nearer yellow1 which shows that this mixture falls between neutral gray and yellow1 partaking somewhat of each4 ,in the same way a line joining yellow and blue shows that their mixture contains both green and gray4 ,indeed1 a line joining any two colors in the circuit may be said to describe their union4 ,a radius crossing this line passes to some hue on the circumference1 and describes by its intersection with the first line the chroma of the color made by a mixture of the two original colors4 ,red ,green make ,yellow-gray ,yellow ,blue ,green-gray ,each pair unites in a colored ,green ,purple ,blue-gray gray1 which is an intermediate hue ,blue ,red ,purple-gray of weak chroma4 ,purple ,yellow ,red-gray ,mixture of white and black3 a scale of grays4 7#fe7 ,so far we have thought only of the plane of the equator1 with its circle of middle hues in ten steps1 and studied their mixture by drawing lines to join them4 ,now let us start at the neutral centre1 and think upward to white and downward to black 7,fig4 #i47 ,illustration3 ,fig4 #i4 ,this vertical line is the neutral axis joining the poles of white and black1 which represent the opposites of light and darkness4 ,middle gray is half-way between4 ,if black is called #j1 and white is #aj1 then the middle point is #e1 with #f1 #g1 #h1 and #i above1 while #d1 #c1 #b1 and #a are below1 thus making a vertical scale of grays from black to white 7,chapter ,,ii41 paragraph #be74 ,if left to personal preference1 an estimate of middle value will vary with each individual who attempts to make it4 ,this appears in the neutral scales already published for schools1 and students who depend upon them1 discover a variation of over #aj per cent4 in the selection of middle gray4 ,since this ,,value ,,scale underlies all color work1 it needs accurate adjustment by scientific means1 as in scales of sound1 of length1 of weight1 or of temperature4 ,a ,,photometer 7photo1 light1 and meter1 a measure7#ai is shown on the next page4 ,it measures the relative amount of light which the eye receives from any source1 and so enables us to make a scale with any number of regular steps4 ,the principle on which it acts is very simple4 ,footnote #ai3 ,adopted in ,course on ,optical ,measurements at the ,massachusetts ,institute of ,technology4 ,instruments have also been made for the ,harvard ,medical ,school1 the ,treasury ,department in ,washington1 and various private laboratories4 ,a rectangular box1 divided by a central partition into halves1 has symmetrical openings in the front walls1 which permit the light to reach two white fields placed upon the back walls4 ,if one looks in through the observation tube1 both halves are seen to be exactly alike1 and the white fields equally illuminated4 ,a valve is then fitted to one of the front openings1 so that the light in that half of the photometer may be gradually diminished4 ,its white field is thus darkened by measured degrees1 and becomes black when all light is excluded by the closed valve4 ,while this darkening process goes on in one-half of the instrument1 the white field in the other half does not change1 and1 looking into the eyepiece1 the observer sees each step contrasted with the original white4 ,one-half is thus said to be variable because of its valve1 and the other side is said to be fixed4 ,a dial connected with the valve has a hand moving over it to show how much light is admitted to the field in the variable half4 ,let us now test one of these personal decisions about middle value4 ,a sample replaces the white field in the fixed half1 and by means of the valve1 the white field in the variable half is alternately darkened and lightened1 until it matches the sample and the eye sees no difference in the two4 ,the dial then discloses the fact that this supposedly ,,middle ,,value reflects only #db per cent4 of the light2 that is to say1 it is nearly a whole step too low in a decimal scale4 ,other samples err nearly as far on the light side of middle value1 and further tests prove not only the varying color sensitiveness of individuals1 but detect a difference between the left and right eye of the same person4 ,illustration3 ,,photometer4 ,back ,view4 ,front ,view4 ,the vagaries of color estimate thus disclosed1 lead some to seek shelter in feeling and inspiration2 but feeling and inspiration are temperamental1 and have nothing to do with the simple facts of vision4 ,a measured and unchanging scale is as necessary and valuable in the training of the eye as the musical scale in the discipline of the ear4 ,it will soon be necessary to talk of the values in each color4 ,we may distinguish the values on the neutral axis from color values by writing them ,n#a1 ,n#b1 ,n#c1 ,n#d1 ,n#e1 ,n#f1 ,n#g1 ,n#h1 ,n#i1 ,n#aj4 ,such a scale makes it easy to foresee the result of mixing light values with dark ones4 ,any two gray values unite to form a gray midway between them4 ,thus ,n#d and ,n#f being equally above and below the centre1 unite to form ,n#e1 as will also ,n#g and ,n#c1 ,n#h and ,n#b1 or ,n#i and ,n#a4 ,but ,n#i and ,n#c will unite to form ,n#f1 which is midway between #f and #i4 ,illustration3 ,vertical ,section through light openings4 ,,parts4 ,c1 ,,cabinet1 with sample-holder 7,h7 and mirror 7,m71 which may be removed and stored to left of dial 7,d7 when instrument is closed for transportation4 ,d1 ,,dial3 records color values in terms of standard white 7#ajj71 the opposite end of the scale being absolute blackness 7#j74 ,e1 ,,eye-,,piece3 to shield eye and sample from extraneous light while color determinations are being made4 ,fatigue of retina should be avoided4 ,g1 ,,gear3 actuates cat's-eye shutter1 which controls amount of light admitted to right half of instrument4 ,its shaft carries index-hand over dial4 ,h1 ,,field-,,holder3 retains sample and standard white in same plane1 and isolates them4 ,is hinged upon lower edge1 and secured by pivot clamp4 ,m1 ,,mirror3 permits observation of the isolated halves of the holder1 bearing standard white and the color to be measured4 ,should be clean and free from dust on both sides of central partition4 ,s1 ,,diffusing ,,screen1 placed over front apertures1 to evenly distribute the light4 7#ff7 ,when this numbered scale of values is familiar1 it serves not only to describe light and dark grays1 but the value of colors which are at the same level in the scale4 ,thus ,r#g 7popularly called a tint of red7 is neither lighter nor darker than the gray of ,n#g4 ,a numeral written above to the right always indicates value1 whether of a gray or a color1 so that ,r#a1 ,r#b1 ,r#c1 ,r#d1 ,r#e1 ,r#f1 ,r#g1 ,r#h1 ,r#i1 describes a regular scale of red values from black to white1 while ,g#a1 ,g#b1 ,g#c1 etc41 is a scale of green values4 7#fg7 ,this matter of a notation for colors will be more fully worked out in ,chapter ,,vi41 but the letters and numerals already described greatly simplify what we are about to consider in the mixture and balance of colors4 ,mixture of light hues with dark hues4 7#fh7 ,now that we are supplied with a decimal scale of grays1 represented by divisions of the neutral axis 7,n#a1 ,n#b1 etc471 and a corresponding decimal scale of value for each of the ten hues ranged about the equator 7,r#a1 ,r#b1-- ,,yr#a1 ,,yr#b1-- ,y#a1 ,y#b1-- ,,gy#a1 ,,gy#b1-- and so on71 traced by ten equidistant meridians from black to white1 it is not difficult to foresee what the mixture of any two colors will produce1 whether they are of the same level of value1 as in the colors of the equator already considered1 or whether they are of different levels4 ,illustration3 ,fig4 #aj4 7#fi7 ,for instance1 let us mix a light yellow 7,y#g7 with a dark red 7,r#c74 ,they are neighbors in hue1 but well removed in value4 ,a line joining them centres at ,,yr#e4 ,this describes the result of their mixture1--a value intermediate between #g and #c1 with a hue intermediate between ,r and ,y4 ,it is a yellow-red of middle value1 popularly called dark orange4 ,but1 while this term dark orange rarely means the same color to three different people1 these measured scales give to ,,yr#e an unmistakable meaning1 just as the musical scale gives an unmistakable significance to the notes of its score4 7#gj7 ,evidently1 this way of writing colors by their degrees of value and hue gives clearness to what would otherwise be hard to express by the color terms in common use4 7#ga7 ,if ,y#i and ,r#e be chosen for mixture1 we know at once that they unite in ,,yr#g1 which is two steps of the value scale above the middle2 while ,y#f and ,r#b make ,,yr#d1 which is one step below the middle4 ,charts prepared with this system show each of these colors and their mixture with exactness4 7#gb7 ,the foregoing mixtures of dark reds and light yellows are typical of the union of light and dark values of any neighboring hues1 such as yellow and green1 green and blue1 blue and purple1 or purple and red4 ,next let us think of the result of mixing different values in opposite hues2 as1 for instance1 ,,yr#g and ,b#c 7,fig4 #aa74 ,to this combination the color sphere gives a ready answer2 for the middle of a straight line through the sphere1 and joining them1 coincides with the neutral centre1 showing that they balance in neutral gray4 ,this is also true of any opposite pair of surface hues where the values are equally removed from the equator4 ,illustration3 ,fig4 #aa4 7#gc7 ,suppose we substitute familiar flowers for the notation1 then ,,yr#g becomes the buttercup1 and ,b#c is the wild violet4 ,but1 in comparing the two1 the eye is more stimulated by the buttercup than by the violet1 not alone because it is lighter1 but because it is stronger in chroma2 that is1 farther away from the neutral axis of the sphere1 and in fact out beyond its surface1 as shown in ,fig4 #aa4 ,the head of a pin stuck in toward the axis on the #gth level of ,,yr may represent the #ith step in the scale of chroma1 such as the buttercup1 while the modest violet with a chroma of only #d1 is shown by its position to be nearer the neutral axis than the brilliant buttercup by five steps of chroma4 ,this is the third dimension of color1 and must be included in our notation4 ,so we write the buttercup ,,yr #g_/i and the violet ,b #c_/d1--;chroma always being written below to the right of hue1 and value always above4 7,this is the invariable order3 ,,hue ,,value_/,,chroma47 7#gd7 ,a line joining the head of the pin mentioned above with ,b #c_/d does not pass through the centre of the sphere1 and its middle point is nearer the buttercup than the neutral axis1 showing that the hues of the buttercup and violet do not balance in gray4 ,the neutral centre is a balancing point for colors4 7#ge7 ,this raises the question1 ,what is balance of color8 ,artists criticise the color schemes of paintings as being too light or too dark 7unbalanced in value71 too weak or too strong 7unbalanced in chroma71 and too hot or too cold 7unbalanced in hue71 showing that this is a fundamental idea underlying all color arrangements4 7#gf7 ,let us assume that the centre of the sphere is the natural balancing point for all colors 7which will be best shown by ,maxwell discs in ,chapter ,v41 paragraphs #ajf-aab71 then color points equally removed from the centre must balance one another4 ,thus white balances black4 ,lighter red balances darker blue-green4 ,middle red balances middle blue-green4 ,in short1 every straight line through this centre indicates opposite qualities that balance one another4 ,the color points so found are said to be complementary1 for each supplies what is needed to complement or balance the other in hue1 value1 and chroma4 7#gg7 ,the true complement of the buttercup1 then1 is not the violet1 which is too weak in chroma to balance its strong opposite4 ,we have no blue flower that can equal the chroma of the buttercup4 ,some other means must be found to produce a balance4 ,one way is to use more of the weaker color4 ,thus we can make a bunch of buttercups and violets1 using twice as many of the latter1 so that the eye sees an area of blue twice as great as the area of yellow-red4 ,area as a compensation for inequalities of hue1 value1 and chroma will be further described under the harmony of color in ,chapter ,,vii4 7#gh7 ,but1 before leaving this illustration of the buttercup and violet1 it is well to consider another color path connecting them which does not pass through the sphere1 but around it 7,fig4 #ab74 ,such a path swinging around from yellow-red to blue slants downward in value1 and passes through yellow1 green-yellow1 green1 and blue-green1 tracing a sequence of hue1 of which each step is less chromatic than its predecessor4 ,illustration3 ,fig4 #ab4 ,this diminishing sequence is easily written thus1--,,yr #h_/i1 ,y #g_/h1 ,,gy #f_/g1 ,g #e_/f1 ,,bg #d_/e1 ,b #c_/d1--;and is shown graphically in ,fig4 #ab4 ,its hue sequence is described by the initials ,,yr1 ,y1 ,,gy1 ,g1 ,,bg1 and ,b4 ,its value-sequence appears in the upper numerals1 #h1 #g1 #f1 #e1 #d1 and #c1 while the chroma-sequence is included in the lower numerals1 #i1 #h1 #g1 #f1 #e1 and #d4 ,this gives a complete statement of the sequence1 defining its peculiarity1 that at each change of hue there is a regular decrease of value and chroma4 ,nature seems to be partial to this sequence1 constantly reiterating it in yellow flowers with their darker green leaves and underlying shadows4 ,in spring time she may contract its range1 making the blue more green and the yellow less red1 but in autumn she seems to widen the range1 presenting strong contrasts of yellow-red and purple-blue4 7#gi7 ,every day she plays upon the values of this sequence1 from the strong contrasts of light and shadow at noon to the hardly perceptible differences at twilight4 ,the chroma of this sequence expands during the summer to strong colors1 and contracts in winter to grays4 ,indeed1 ,nature1 who would seem to be the source of our notions of color harmony1 rarely repeats herself1 yet is endlessly balancing inequalities of hue1 value1 and chroma by compensations of quantity4 7#hj7 ,so subtle is this equilibrium that it is taken for granted and forgotten1 except when some violent disturbance disarranges it1 such as an earthquake or a thunder-storm4 ,the triple nature of color balance illustrated4 7#ha7 ,the simplest idea of balance is the equilibrium of two halves of a stick supported at its middle point4 ,if one end is heavier than the other1 the support must be moved nearer to that end4 ,but1 since color unites three qualities1 we must seek some type of triple balance4 ,the game of jackstraws illustrates this1 when the disturbance of one piece involves the displacement of two others4 ,the action of three children on a floating plank or the equilibrium of two acrobats carried on the shoulders of a third may also serve as examples4 ,illustration3 ,fig4 #ad4 7#hb7 ,triple balance may be graphically shown by three discs in contact4 ,two of them are suspended by their centres1 while they remain in touch with a third supported on a pivot1 as in ,fig4 #ad4 ,let us call the lowest disc ,hue 7,h71 and the lateral discs ,value 7,v7 and ,chroma 7,c74 ,any dip or rotation of the lower disc ,h will induce sympathetic action in the two lateral discs ,v and ,c4 ,when ,h is inclined1 both ,v and ,c change their relations to it4 ,if ,h is raised vertically1 both ,v and ,c dip outward4 ,if ,h is rotated1 both ,v and ,c rotate1 but in opposite directions4 ,indeed1 any disturbance of ,v affects ,h and ,c1 while ,h and ,v respond to any movement of ,c4 ,so we must be prepared to realize that any change of one color quality involves readjustment of the other two4 7#hc7 ,color balance soon leads to a study of optics in one direction1 to sthetics in another1 and to mathematical proportions in a third1 and any attempt at an easy solution of its problems is not likely to succeed4 ,it is a very complicated question1 whose closest counterpart is to be sought in musical rhythms4 ,the fall of musical impulses upon the ear can make us gay or sad1 and there are color groups which1 acting through the eye1 can convey pleasure or pain to the mind4 7#hd7 ,a colorist is keenly alive to these feelings of satisfaction or annoyance1 and consciously or unconsciously he rejects certain combinations of color and accepts others4 ,successful pictures and decorative schemes are due to some sort of balance uniting light and shade 7value71 warmth and coolness 7hue71 with brilliancy and grayness 7chroma72 for1 when they fail to please1 the mind at once begins to search for the unbalanced quality1 and complains that the color is too hot1 too dark1 or too crude4 ,this effort to establish pleasing proportions may be unconscious in one temperament1 while it becomes a matter of definite analysis in another4 ,emerson claimed that the unconscious only is complete4 ,we gladly permit those whose color instinct is unerring--7and how few they are67--to neglect all rules and set formulas4 ,but education is concerned with the many who have not this gift4 7#he7 ,any real progress in color education must come not from a blind imitation of past successes1 but by a study into the laws which they exemplify4 ,to exactly copy fine ,japanese prints or ,persian rugs or ,renaissance tapestries1 while it cultivates an appreciation of their refinements1 does not give one the power to create things equally beautiful4 ,the masterpieces of music correctly rendered do not of necessity make a composer4 ,the musician1 besides the study of masterpieces1 absorbs the science of counterpoint1 and records by an unmistakable notation the exact character of any new combination of musical intervals which he conceives4 7#hf7 ,so must the art of the colorist be furnished with a scientific basis and a clear form of color notation4 ,this will record the successes and failures of the past1 and aid in a search1 by contrast and analysis1 for the fundamentals of color balance4 ,without a measured and systematic notation1 attempts to describe color harmony only produce hazy generalities of little value in describing our sensations1 and fail to express the essential differences between good and bad color4 ,,appendix ,,to ,,chapter ,,iii4 ,illustration ,,false ,,color ,,balance4 ,there is a widely accepted error that red1 yellow1 and blue are primary1 although ,brewster's theory was long ago dropped when the elements of color vision proved to be ,,red1 ,,green1 and ,,violet-,,blue4 ,the late ,professor ,rood called attention to this in ,chapters ,,viii4-,,xi4 of his book1 ,modern ,chromatics1 which appeared in #ahgi4 ,yet we find it very generally taught in school4 ,nor does the harm end there1 for placing red1 yellow1 and blue equidistant in a circle1 with orange1 green1 and purple as intermediates1 the teacher goes on to state that opposite hues are complementary4 ,red is thus made the complement of ,green1 ,yellow ,purple1 and ,blue ,orange4 ,unfortunately1 each of these statements is wrong1 and1 if tested by the mixture of colored lights or with ,maxwell's rotating discs1 their falsity is evident4 ,there can be no doubt that green is not the complement of red1 nor purple of yellow1 nor orange of blue1 for neither one of these pairs unites as it should in a balanced neutrality1 and a total test of the circle gives great excess of orange1 showing that red and yellow usurp too great a portion of the circumference4 ,starting from a false basis1 the ,brewster theory can only lead to unbalanced and inharmonious effects of color4 ,the fundamental color sensations are ,,red1 ,,green1 and ,,violet-,,blue4 ,,red has for its true complement ,,blue-,,green1 ,,green ,,red-,,purple1 and ,,violet-,,blue ,,yellow1 all of the hues in the right-hand column being compound sensations4 ,the sensation of green is not due to a mixture of yellow and blue1 as the absorptive action of pigments might lead one to think3 ,,green ,,is ,,fundamental1 and not made by mixing any hues of the spectrum1 while ,,yellow ,,is ,,not ,,fundamental1 but caused by the mingled sensations of red and green4 ,this is easily proved by a controlled spectrum1 for all yellow-reds1 yellows1 and green-yellows can be matched by certain proportions of red and green light1 all blue-greens1 blues1 and purple-blues can be obtained by the union of green and violet light1 while purple-blue1 purple1 and red-purple result from the union of violet and red light4 ,but there is no point where a mixture gives red1 green1 or violet-blue4 ,they are the true primaries1 whose mixtures produce all other hues4 ,studio and school-room practice still cling to the discredited theory1 claiming that1 if it fails to describe our color sensations1 yet it may be called practically true of pigments1 because a red1 yellow1 and blue pigment suffice to imitate most natural colors4 ,this discrepancy between pigment mixture and retinal mixture becomes clear as soon as one learns the physical make-up and behavior of paints4 ,illustration3 ,vermilion ,spectra ,em4 ,green ,p4 ,b4 ,g4 ,y4 ,r4 ,spectral analysis shows that no pigment is a pure example of the dominant hue which it sends to the eye4 ,take1 for example1 the very chromatic pigments representing red and green1 such as vermilion and emerald green4 ,if each emitted a single pure hue free from trace of any other hue1 then their mixture would appear yellow1 as when spectral red and green unite4 ,but1 instead of yellow1 their mixture produces a warm gray1 called brown or dull salmon1 and this is to be inferred from their spectra1 where it is seen that vermilion emits some green and purple as well as its dominant color1 while the green also sends some blue and red light to the eye4#bj ,footnote #bj3 ,see ,rood1 ,chapter ,,vii41 on ,color by ,absorption4 ,thus stray hues from other parts of the spectrum tend to neutralize the yellow sensation1 which would be strong if each of the pigments were pure in the spectral sense4 ,pigment absorption affects all palette mixtures1 and1 failing to obtain a satisfactory yellow by mixture of red and green1 painters use original yellow pigments1--such as aureolin1 cadmium1 and lead chromate1--each of them also impure but giving a dominant sensation of yellow4 ,did the eye discriminate1 as does the ear when it analyzes the separate tones of a chord1 then we should recognize that yellow pigments emit both red and green rays4 ,white light dispersed into a colored band by one prism1 may have the process reversed by a second prism1 so that the eye sees again only white light4 ,but this would not be so1 did not the balance of red1 green1 and violet-blue sensations remain undisturbed4 ,all our ideas of color harmony are based upon this fundamental relation1 and1 if pigments are to render harmonious effects1 we must learn to control their impurities so as to preserve a balance of red1 green1 and violet-blue4 ,otherwise1 the excessive chroma and value of red and yellow pigments so overwhelm the lesser degrees of green and blue pigments that no balance is possible1 and the colorist of fine perception must reject not alone the theoretical1 but also the practical outcome of a red-yellow-blue theory4 ,some of the points raised in this discussion are rather subtle for students1 and may well be left until they arise in a study of optics1 but the teacher should grasp them clearly1 so as not to be led into false statements about primary and complementary hues4 ,,chapter ,,iv4 ,,prismatic ,,color4 ,pure color is seen in the spectrum of sunlight4 7#hg7 ,the strongest sensation of color is gained in a darkened room1 with a prism used to split a beam of sunlight into its various wave lengths4 ,through a narrow slit there enters a straight pencil of light which we are accustomed to think of as white1 although it is a bundle of variously colored rays 7or waves of ether7 whose union and balance is so perfect that no single ray predominates4 ,illustration3 ,fig4 #ac4 7#hh7 ,cover the narrow slit1 and we are plunged in darkness4 ,admit the beam1 and the eye feels a powerful contrast between the spot of light on the floor and its surrounding darkness4 ,place a triangular glass prism near the slit to intercept the beam of white light1 and suddenly there appears on the opposite wall a band of brilliant colors4 ,this delightful experiment rivets the eye by the beauty and purity of its hues4 ,all other colors seem weak by comparison4 ,their weakness is due to impurity1 for all pigments and dyes reflect portions of hues other than their dominant one1 which tend to gray and diminish their chroma4 7#hi7 ,but prismatic color is pure1 or very nearly so1 because the shape of the glass refracts each hue1 and separates it by the length of its ether wave4 ,these waves have been measured1 and science can name each hue by its wave length4 ,thus a certain red is known as ,m4 #fhfg1 and a certain green sensation is ,m4 #ebfi4ba ,without attempting any scientific analysis of color1 let it be said that ,sir ,isaac ,newton made his series of experiments in #afhg1 and was privileged to name this color sequence by seven steps which he called red1 orange1 yellow1 green1 blue1 violet1 and indigo4 ,later a scientist named ,fraunhofer discovered fine black lines crossing the solar spectrum1 and marked them with letters of the alphabet from a to h4 ,these with the wave length serve to locate every hue and define every step in the sequence4 ,since ,newton's time it has been proved that only three of the spectral hues are primary2 viz41 a red1 a green1 and a violet-blue1 while their mixture produces all other gradations4 ,by receiving the spectrum on an opaque screen with fine slits that fit the red and green waves1 so that they alone pass through1 these two primary hues can be received on mirrors inclined at such an angle as to unite on another screen1 where1 instead of red or green1 the eye sees only yellow4#bb ,footnote #ba3 ,see ,micron in ,glossary4 ,footnote #bb3 ,the fact that the spectral union of red and green makes yellow is a matter of surprise to practical workers in color who are familiar with the action of pigments1 but unfamiliar with spectrum analysis4 ,yellow seems to them a primary and indispensable color1 because it cannot be made by the union of red and green pigments4 ,another surprise is awaiting them when they hear that the yellow and blue of the spectrum make white1 for all their experience with paints goes to prove that yellow and blue unite to form green4 ,attention is called to this difference between the mixture of colored light and of colored pigments1 not with the idea of explaining it here1 but to emphasize their difference2 for in the next chapter we shall describe the practical making of a color sphere with pigments1 which would be quite impractical1 could we have only the colors of the spectrum to work with4 ,see ,appendix to preceding chapter4 7#ij7 ,a similar arrangement of slits and mirrors for the green and violet-blue proves that they unite to make blue1 while a third experiment shows that the red and violet-blue can unite to make purple4 ,so yellow1 blue-green1 and purple are called secondary hues because they result from the mixture of the three primaries1 red1 green1 and violet-blue4 ,in comparing these two color lists1 we see that the indigo and orange of ,sir ,isaac ,newton have been discarded4 ,both are indefinite1 and refer to variable products of the vegetable kingdom4 ,violet is also borrowed from the same kingdom2 and1 in order to describe a violet1 we say it is a purple violet or blue violet1 as the case may be1 just as we describe an orange as a red orange or a yellow orange4 ,their color difference is not expressed by the terms orange or violet1 but by the words red1 yellow1 blue1 or purple1 all of which are true color names and arouse an unmixed color image4 7#ia7 ,in the nursery a child learns to use the simple color names red1 yellow1 green1 blue1 and purple4 ,when familiarity with the color sphere makes him relate them to each other and place them between black and white by their degree of light and strength1 there will be no occasion to revert to vegetables1 animals1 minerals1 or the ever-varying hues of sea and sky to express his color sensations4 7#ib7 ,another experiment accentuates the difference between spectral and pigment color4 ,when the spectrum is spread on the screen by the use of a prism1 and a second prism is placed inverted beyond the first1 it regathers the dispersed rays back into their original beam1 making a white spot on the floor4 ,this proves that all the colored rays of light combine to balance each other in whiteness4 ,but if pigments which are the closest possible imitation of these hues are united on a painter's palette1 either by the brush or the knife1 they make gray1 and not white4 7#ic7 ,this is another illustration of the behavior of pigments1 for1 instead of uniting to form white1 they form gray1 which is a darkened or impure form of white2 and1 lest this should be attributed to a chemical reaction between the various matters that serve as pigments1 the experiment can be carried out without allowing one pigment to touch another by using ,maxwell discs1 as will be shown in the next chapter4 7#id7 ,before leaving these prismatic colors1 let us study them in the light of what has already been learned of color dimensions4 ,not only do they present different values1 but also different chromas4 ,their values range from darkness at each end1 where red and purple become visible1 to a brightness in the greenish yellow1 which is almost white4 ,so on the color tree described in ,chapter ,,ii41 paragraph #cd1 yellow has the highest branch1 green is lower1 red is below the middle1 with blue and purple lower down1 near black4 ,illustration3 ,fig4 #ae4 7#ie7 ,then in chroma they range from the powerful stimulation of the red to the soothing purple1 with green occupying an intermediate step4 ,this is also given on the color tree by the length of its branches4 7#if7 ,in ,fig4 #ae the vertical curve describes the values of the spectrum as they grade from red through yellow1 green1 blue1 and purple4 ,the horizontal curve describes the chromas of the spectrum in the same sequence2 while the third curve leaning outward is obtained by uniting the first two by two planes at right angles to one another1 and sums up the three qualities by a single descriptive line4 ,now the red and purple ends are far apart1 and science forbids their junction because of their great difference in wave length4 ,but the mind is prone to unite them in order to produce the red-purples which we see in clouds at sunset1 in flowers and grapes and the amethyst4 ,indeed1 it has been done unhesitatingly in most color schemes in order to supply the opposite of green4 7#ig7 ,this gives a slanting circuit joining all the branch ends of the color tree1 and has been likened to the rings of ,saturn in ,chapter ,i41 paragraph #ag4 ,a prismatic color sphere4 7#ih7 ,with a little effort of the imagination we can picture a prismatic color sphere1 using only the colors of light4 ,in a cylindrical chamber is hung a diaphanous ball similar to a huge soap bubble1 which can display color on its surface without obscuring its interior4 ,then1 at the proper points of the surrounding wall1 three pure beams of colored light are admitted1--one red1 another green1 and the third violet-blue4 7#ii7 ,they fall at proper levels on three sides of the sphere1 while their intermediate gradations encircle the sphere with a complete spectrum plus the needed purple4 ,as they penetrate the sphere1 they unite to balance each other in neutrality4 ,pure whiteness is at the top1 and1 by some imaginary means their light gradually diminishes until they disappear in darkness below4 7#ajj7 ,this ideal color system is impossible in the present state of our knowledge and implements4 ,even were it possible1 its immaterial hues could not serve to dye materials or paint pictures4 ,pigments are1 and will in all probability continue to be1 the practical agents of coloristic productions1 however reluctant the scientist may be to accept them as the basis of a color system4 ,it is true that they are chemically impure and imperfectly represent the colors of light4 ,some of them fade rapidly and undergo chemical change1 as in the notable case of a green pigment tested by this measured system1 which in a few weeks lost four steps of chroma1 gained two steps of value1 and swung into a bluer hue4 7#aja7 ,but the color sphere to be next described is worked out with a few reliable pigments1 mostly natural earths1 whose fading is a matter of years and so slight as to be almost imperceptible4 ,besides1 its principal hues are preserved in safe keeping by imperishable enamels1 which can be used to correct any tendency of the pigments to distort the measured intervals of the color sphere4 ,this meets the most serious objection to a pigment system4 ,without it a child has nothing tangible which he can keep in constant view to imitate and memorize4 ,with it he builds up a mental image of measured relations that describe every color in nature1 including the fleeting hues of the rainbow1 although they appear but for a moment at rare intervals4 ,finally1 it furnishes a simple notation which records every color sensation by a letter and two numerals4 ,with the enlargement of his mental power he will unite these in a comprehensive grasp of the larger relations of color4 ,,appendix ,,to ,,chapter ,,iv4 ,children's ,color ,studies4 ,these reproductions of children's work are given as proof that color charm and good taste may be cultivated from the start4 ,,five ,,middle ,,hues are first taught by the use of special crayons1 and later with water colors4 ,they represent the equator of the color sphere 7see ,plate ,i471--a circle midway between the extremes of color-light and color-strength1--and are known as ,,middle ,,red1 ,,middle ,,yellow1 ,,middle ,,green1 ,,middle ,,blue1 and ,,middle ,,purple4 ,these are starting-points for training the eye to measure regular scales of ,value and ,chroma4#bc ,only with such a trained judgment is it safe to undertake the use of strong colors4#bd ,footnote #bc3 ,see ,century ,dictionary for definition of chroma4 ,under the word color will be found definitions of ,primary1 ,complementary1 ,constants 7chroma1 luminosity1 and hue71 and the ,young-,helmholtz theory of color-sensation4 ,footnote #bd3 ,it must not be assumed because so much stress is laid upon quiet and harmonious color that this system excludes the more powerful degrees4 ,to do so would forfeit its claim to completeness4 ,a ,color ,atlas in preparation displays all known degrees of pigment color arranged in measured scales of ,hue1 ,value1 and ,chroma4 ,beginners should avoid ,strong ,color4 ,extreme red1 yellow1 and blue are discordant4 7,they shriek and swear4 ,mark ,twain calls ,roxana's gown a volcanic eruption of infernal splendors47 ,yet there are some who claim that the child craves them1 and must have them to produce a thrill4 ,so also does he crave candies1 matches1 and the carving-knife4 ,he covets the trumpet1 fire-gong1 and bass-drum for their thrill2 but who would think them necessary to the musical training of the ear8 ,like the blazing bill-board and the circus wagon1 they may be suffered out-of-doors2 but such boisterous sounds and color sprees are unfit for the school-room4 ,quiet ,color is the ,mark of ,good ,taste4 ,refinement in dress and the furnishings of the home is attractive1 but we shrink from those who are loud in their speech or their clothing4 ,if we wish our children to become well-bred1 is it logical to begin by encouraging barbarous tastes8 ,their young minds are very open to suggestion4 ,they quickly adopt our standards1 and the blame must fall upon us if they acquire crude color habits4 ,yellow journalism and rag-time tunes will not help their taste in speech or song1 nor will violent hues improve their taste in matters of color4 ,balance of ,color is to be sought4 ,artists and decorators are well aware of a fact that slowly dawns upon the student2 namely1 that color harmony is due to the preservation of a subtle balance and impossible by the use of extremes4 ,this balance of color resides more within the spherical surface of this system than in the excessive chromas which project beyond4 ,it is futile to encourage children in efforts to rival the poppy or buttercup1 even with the strongest pigments obtainable4 ,their sunlit points give pleasure because they are surrounded and balanced by blue ether and wide green fields4 ,were these conditions reversed1 so that the flowers appeared as little spots of blue or green in great fields of blazing red1 orange1 and yellow1 our pained eyes would be shut in disgust4 ,the painter knows that pigments cannot rival the brilliancy of the buttercup and poppy1 enhanced by their surroundings4 ,what is more1 he does not care to attempt it4 ,nor does the musician wish to imitate the screech of a siren or the explosion of a gun4 ,these are not subjects for art4 ,harmonious sounds are the study of the musician1 and tuned colors are the materials of the colorist4 ,corot in landscape1 and ,titian1 ,velasquez1 and ,whistler in figure painting1 show us that ,nature's richest effects and most beautiful color are enveloped in an atmosphere of gray4 ,beauty of ,color lies in ,tempered ,relations4 ,music rarely touches the extreme range of sound1 and harmonious color rarely uses the extremes of color-light or color-strength4 ,regular scales in the middle register are first given to train the ear1 and so should the eye be first familiarized with medium degrees of color4 ,this system provides measured scales1 established by special instruments1 and is able to select the middle points of red1 yellow1 green1 blue1 and purple as a basis for comparing and relating all colors4 ,these five middle colors form a ,chromatic ,tuning ,fork4 7,see page #gj47 ,it is far better that children should first become familiar with these tuned color intervals which are harmonious in themselves rather than begin by blundering among unrelated degrees of harsh and violent color4 ,who would think of teaching the musical scale with a piano out of tune8 ,the ,tuning of ,color cannot be left to ,personal ,whim4 ,the wide discrepancies of red1 yellow1 and blue1 which have been falsely taught as primary colors1 can no more be tuned by a child than the musical novice can tune his instrument4 ,each of these hues has three variable factors 7see page #ad1 paragraph #ad71 and scientific tests are necessary to measure and relate their uneven degrees of ,hue1 ,value1 and ,chroma4 ,visual estimates of color1 without the help of any standard for comparison1 are continually distorted by doubt1 guess-work1 and the fatigue of the eye4 ,hardly two persons can agree in the intelligible description of color4 ,not only do individuals differ1 but the same eye will vary in its estimates from day to day4 ,a frequent assumption that all strong pigments are equal in chroma1 is far from the truth1 and involves beginners in many mishaps4 ,thus the strongest blue-green1 chromium sesquioxide1 is but half the chroma of its red complement1 the sulphuret of mercury4 ,yet ignorance is constantly leading to their unbalanced use4 ,indeed1 some are still unaware that they are the complements of each other4#be ,footnote #be3 ,see ,appendix to ,chapter ,,iii4 ,it is evident that the fundamental scales of ,hue1 ,value1 and ,chroma must be established by scientific measures1 not by personal bias4 ,this system is unique in the possession of such scales1 made possible by the devising of special instruments for the measurement of color1 and can therefore be trusted as a permanent basis for training the color sense4 ,the examples in ,plates ,,ii4 and ,,iii4 show how successfully the tuned crayons1 cards1 and water colors of this system lead a child to fine appreciations of color harmony4 ,,plate ,,ii4 ,,color ,,studies ,,with ,,tuned ,,crayons ,,in ,,the ,,lower ,,grades4 ,children have made every example on this plate1 with no other material than the five crayons of middle hue1 tempered with gray and black4 ,a ,color ,sphere is always kept in the room for reference1 and five color balls to match the five middle hues are placed in the hands of the youngest pupils4 ,starting with these middle points in the scales of ,value and ,chroma1 they learn to estimate rightly all lighter and darker values1 all weaker and stronger chromas1 and gradually build up a disciplined judgment of color4 ,each study can be made the basis of many variations by a simple change of one color element1 as suggested in the text4 #a4 ,butterfly4 ,yellow and black crayon4 ,vary by using any single crayon with black4 #b4 ,dish4 ,red crayon1 blue and green crayons for back and foreground4 ,vary by using the two opposites of any color chosen for the dish and omitting the two neighboring colors4 ,see ,no4 #d4 #c4 ,hiawatha's canoe4 ,yellow crayon1 with rim and name in green4 ,vary color of canoe1 keeping the rim a neighboring color4 ,see ,no4 #d4 #d4 ,color-circle4 ,gray crayon for centre1 and five crayons spaced equidistant4 ,this gives the invariable order1 red1 yellow1 green1 blue1 purple4 ,never use all five in a single design4 ,either use a color and its two neighbors or a color and its two opposites4 ,by mingling touches of any two neighbors1 the intermediates are made and named yellow-red 7orange71 green-yellow1 blue-green1 purple-blue 7violet71 and red-purple4 ,abbreviated1 the circle reads ,r1 ,,yr1 ,y1 ,,gy1 ,g1 ,,bg1 ,b1 ,,pb1 ,p1 ,,rp4 #e4 ,rosette4 ,red cross in centre1 green leaves3 blue field1 black outline4 ,vary as in ,no4 #b4 #f4 ,rosette4 ,green centre and edge of leaves1 purple field and black accents4 ,vary color of centre1 keeping field two colors distant4 #g4 ,plaid4 ,use any three crayons with black4 ,vary the trio4 #h4 ,folding screen4 ,yellow field 7lightly applied71 green and black edge4 ,make lighter and darker values of each color1 and arrange in scales graded from black to white4 #i4 ,rug4 ,light red field with solid red centre1 border pattern and edges of gray4 ,this is called self-color4 ,change to each of the crayons4 #aj4 ,rug4 ,light yellow field and solid centre1 with purple and black in border design4 ,vary by change of ground1 keeping design two colors distant and darkened with black4 #aa4 ,lattice4 ,yellow with black3 alternate green and blue lozenges4 ,vary by keeping the lozenges of two neighboring colors1 but one color removed from that of the lattice4 ,for principles involved in these color groups1 see ,chapter ,,iii4 ,,plate ,,iii4 ,,color ,,studies ,,with ,,tuned ,,water ,,colors ,,in ,,the ,,upper ,,grades4 ,previous work with measured scales1 made by the tuned crayons and tested by reference to the color sphere1 have so trained the color judgment that children may now be trusted with more flexible material4 ,they have memorized the equable degrees of color on the equator of the sphere1 and found how lighter colors may balance darker colors1 how small areas of stronger chroma may be balanced by larger masses of weaker chroma1 and in general gained a disciplined color sense4 ,definite impressions and clear thinking have taken the place of guess-work and blundering4 ,thus1 before reaching the secondary school1 they are put in possession of the color faculty by a system and notation similar to that which was devised centuries ago for the musical sense4 ,no system1 however logical1 will produce the artist1 but every artist needs some systematic training at the outset1 and this simple method by measured scales is believed to be the best yet devised4 ,illustration3 ,,plate #b4 ,copyright #aijg by ,a4 ,h4 ,munsell ,illustration3 ,,plate #c4 ,copyright #aijg by ,a4 ,h4 ,munsell ,each example on this plate may be made the basis of many variants1 by small changes in the color steps1 as suggested in the text1 and further elaborated in ,chapter ,,vi4 ,indeed1 the studies reproduced on ,plates ,,ii4 and ,,iii4 are but a handful among hundreds of pleasing results produced in a single school4#bf #a4 ,pattern4 ,purple and green3 the two united and thinned with water will give the ground4 ,vary with any other color pair4 #b4 ,pattern4 ,figure in middle red1 with darker blue-green accent4 ,ground of middle yellow1 grayed with slight addition of the red and green4 ,vary with purple in place of blue-green4 #c4 ,japanese teapot4 ,middle red1 with background of lighter yellow and foreground of grayed middle yellow4 #d4 ,variant on ,no4 #c4 ,middle yellow1 with slight addition of green4 ,foreground the same1 with more red1 and background of middle gray4 #e4 ,group4 ,background of yellow-red1 lighter vase in yellow-green1 and darker vase of green1 with slight addition of black4 ,vary by inversion of the colors in ground and darker vase4 #f4 ,wall decoration4 ,frieze pattern made of cat-tails and leaves1--the leaves of blue-green with black1 tails of yellow-red with black1 and ground of the two colors united and thinned with water4 ,wall of blue-green1 slightly grayed by additions of the two colors in the frieze4 ,dado could be a match of the cat-tails slightly grayer4 ,see ,fig4 #bc1 page #hb4 #g4 ,group4 ,foreground in purple-blue1 grayed with black4 ,vase of purple-red1 and background in lighter yellow-red1 grayed4 ,for analysis of the groups and means of recording them1 see ,chapter ,,iii4 ,footnote #bf3 ,the ,pope ,school1 ,somerville1 ,mass4 ,,chapter ,v4 ,a ,,pigment ,,color ,,sphere4#bg ,how to make a color sphere with pigments4 7#ajb7 ,the preceding chapters have built up an ideal color solid1 in which every sensation of color finds its place and is clearly named by its degree of hue1 value1 and chroma4 ,illustration3 ,fig4 #af4 ,it has been shown that the neutral centre of the system is a balancing point for all colors1 that a line through this centre finds opposite colors which balance and complement each other2 and we are now ready to make a practical application1 carrying out these ideal relations of color as far as pigments will permit in a color sphere#bg 7,fig4 #af74 ,footnote #bg3 ,patented ,jan4 #i1 #aijj4 7#ajc7 ,the materials are quite simple4 ,first a colorless globe1 mounted so as to spin freely on its axis4 ,then a measured scale of value1 specially devised for this purpose1 obtained by the daylight photometer4#bh ,next a set of carefully chosen pigments1 whose reasonable permanence has been tested by long use1 and which are prepared so that they will not glisten when spread on the surface of the globe1 but give a uniformly mat surface4 ,a glass palette1 palette knife1 and some fine brushes complete the list4 ,footnote #bh3 ,see paragraph #fe4 7#ajd7 ,here is a list of the paints arranged in pairs to represent the five sets of opposite hues described in ,chapter ,,iii41 paragraphs #fa-fc3-- ,color ,pairs4 ,pigments ,used4 ,chemical ,nature4 ,red and ,venetian red4 ,calcined native earth4 ,blue-green4 ,viridian and ,cobalt4 ,chromium sesquioxide4 ,yellow and ,raw ,sienna4 ,native earth4 ,purple-blue4 ,ultramarine4 ,artificial product4 ,green and ,emerald green4 ,arsenate of copper4 ,red-purple4 ,purple madder4 ,extract of the madder plant4 ,blue and ,cobalt4 ,oxide of cobalt with alumina4 ,yellow-red4 ,orange cadmium4 ,sulphide of cadmium4 ,purple and ,madder and cobalt4 ,see each pigment above4 ,green-yellow4 ,emerald green ,see each pigment above4 and ,sienna4 7#aje7 ,these paints have various degrees of hue1 value1 and chroma1 but can be tempered by additions of the neutrals1 zinc white and ivory black1 until each is brought to a middle value and tested on the value scale4 ,after each pair has been thus balanced1 they are painted in their appropriate spaces on the globe1 forming an equator of balanced hues4 ,illustration3 ,fig4 #ag4 7#ajf7 ,the method of proving this balance has already been suggested in ,chapter ,,iv41 paragraph #ic4 ,it consists of an ingenious implement devised by ,clerk-,maxwell1 which gives us a result of mixing colors without the chemical risks of letting them come in contact1 and also measures accurately the quantity of each which is used 7,fig4 #ag74 7#ajg7 ,this is called a ,maxwell disc1 and is nothing more than a circle of firm cardboard1 pierced with a central hole to fit the spindle of a rotary motor1 and with a radial slit from rim to centre1 so that another disc may be slid over the first to cover any desired fraction of its surface4 ,let us paint one of these discs with ,venetian red and the other with viridian and cobalt1 the first pair in the list of pigments to be used on the globe4 7#ajh7 ,having dried these two discs1 one is combined with the other on the motor shaft so that each color occupies half the circle4 ,as soon as the motor starts1 the two colors are no longer distinguished1 and rapid rotation melts them so perfectly that the eye sees a new color1 due to their mixture on the retina4 ,this new color is a reddish gray1 showing that the red is more chromatic than the blue-green4 ,but by stopping the motor and sliding the green disc to cover more of the red one1 there comes a point where rotation melts them into a perfectly neutral gray4 ,no hint of either hue remains1 and the pair is said to balance4 7#aji7 ,since this balance has been obtained by unequal areas of the two pigments1 it must compensate for a lack of equal chroma in the hues 7see paragraphs #gf1 #gg72 and1 to measure this inequality1 a slightly larger disc1 with decimal divisions on its rim1 is placed back of the two painted ones4 ,if this scale shows the red as occupying #c-a_/c parts of the area1 while blue-green occupies #f-b_/c parts1 then the blue-green must be only half as chromatic as the red1 since it takes twice as much to produce the balance4 7#aaj7 ,the red is then grayed 7diminished in chroma by additions of a middle gray7 until it can occupy half the circle1 with blue-green on the remaining half1 and still produce neutrality when mixed by rotation4 ,each disc now reads #e on the decimal scale4 ,lest the graying of red should have disturbed its value1 it is again tested on the photometric scale1 and reads #d4g1 showing it has been slightly darkened by the graying process4 ,a little white is therefore added until its value is restored to #e4 7#aaa7 ,the two opposites are now completely balanced1 for they are equal in value 7#e71 equal in chroma 7#e71 and have proved their equality as complements by uniting in equal areas to form a neutral mixture4 ,it only remains to apply them in their proper position on the sphere4 7#aab7 ,a band is traced around the equator1 divided in ten equal spaces1 and lettered ,r1 ,,yr1 ,y1 ,,gy1 ,g1 ,,bg1 ,b1 ,,pb1 ,p1 and ,,rp 7see ,fig4 #ah74 ,this balanced red and blue-green are applied with the brush to spaces marked ,r and ,,bg1 care being taken to fill1 but not to overstep the bounds1 and the color laid absolutely flat1 that no unevenness of value or chroma may disturb the balance4 7#aac7 ,the next pair1 represented by ,raw ,sienna and ,ultramarine1 is similarly brought to middle value1 balanced by equal areas on the ,maxwell discs1 and1 when correct in each quality1 is painted in the spaces ,y and ,,pb4 ,emerald ,green and ,purple ,madder1 which form the next pigment pair1 are similarly tempered1 proved1 and applied1 followed by the two remaining pairs1 until the equator of the globe presents its ten equal steps of middle hues4 ,an equator of ten balanced hues4 7#aad7 ,now comes the total test of this circuit of balanced hues by rotation of the sphere4 ,as it gains speed1 the colors flash less and less1 and finally melt into a middle gray of perfect neutrality4 ,had it failed to produce this gray and shown a tinge of any hue still persisting1 we should say that the persistent hue was in excess1 or1 conversely1 that its opposite hue was deficient in chroma1 and failed to preserve its share in the balance4 ,illustration3 ,fig4 #ah4 7#aae7 ,for instance1 had rotation discovered the persistence of reddish gray1 it would have proved the red too strong1 or its opposite1 blue-green1 too weak1 and we should have been forced to retrace our steps1 applying a correction until neutrality was established by the rotation test4 7#aaf7 ,this is the practical demonstration of the assertion 7,chapter ,i41 paragraph #h7 that a color has three dimensions which can be measured4 ,each of these ten middle hues has proved its right to a definite place on the color globe by its measurements of value and chroma4 ,being of equal chroma1 all are equidistant from the neutral centre1 and1 being equal in value1 all are equally removed from the poles4 ,if the warm hues 7red and yellow7 or the cool hues 7blue and green7 were in excess1 the rotation test of the sphere would fail to produce grayness1 and so detect its lack of balance4#bi ,footnote #bi3 ,such a test would have exposed the excess of warm color in the schemes of ,runge and ,chevreul1 as shown in the ,appendix to this chapter4 ,a chromatic tuning fork4 7#aag7 ,the five principal steps in this color equator are made in permanent enamel and carefully safeguarded1 so that1 if the pigments painted on the globe should change or become soiled1 it could be at once detected and set right4 ,these five are middle red 7so called because midway between white and black1 as well as midway between our strongest red and the neutral centre71 middle yellow1 middle green1 middle blue1 and middle purple4 ,they may be called the ,,chromatic ,,tuning ,,fork1 for they serve to establish the pitch of colors1 as the musical tuning fork preserves the pitch of sounds4 ,completion of a pigment color sphere4 7#aah7 ,when the chromatic tuning fork has thus been obtained1 the completion of the globe is only a matter of patience1 for the same method can be applied at any level in the scale of value1 and a new circuit of balanced hues made to conform with its position between the poles of white and black4 ,illustration3 ,fig4 #ai4 7#aai7 ,the surface above and below the equatorial band is set off by parallels to match the photometric scale1 making nine bands or value zones in all1 of which the equator is fifth1 the black pole being #j and the white pole #aj4 7#abj7 ,ten meridians carry the equatorial hues across all these value zones and trace the gradation of each hue through a complete scale from black to white1 marked by their values1 as shown in paragraph #fh4 ,thus the red scale is ,r#a1 ,r#b1 ,r#c1 ,r#d1 ,r#e 7middle red71 ,r#f1 ,r#g1 ,r#h1 and ,r#i1 and similarly with each of the other hues4 ,when the circle of hues corresponding to each level has been applied and tested1 the entire surface of the globe is spread with a logical system of color scales1 and the eye gratified with regular sequences which move by measured steps in each direction4 7#aba7 ,each meridian traces a scale of value for the hue in which it lies4 ,each parallel traces a scale of hue for the value at whose level it is drawn4 ,any oblique path across these scales traces a regular sequence1 each step combining change of hue with a change of value and chroma4 ,the more this path approaches the vertical1 the less are its changes of hue and the more its changes of value and chroma2 while1 the nearer it comes to the horizontal1 the less are its changes of value and chroma1 while the greater become its changes of hue4 ,of these two oblique paths the first may be called that of a ,luminist1 or painter like ,rembrandt1 whose canvases present great contrasts of light and shade1 while the second is that of the ,colorist1 such as ,titian1 whose work shows great fulness of hues without the violent extremes of white and black4 ,total balance of the sphere tested by rotation on any desired axis4 7#abb7 ,not only does the mount of the color sphere permit its rotation on the vertical axis 7white-black71 but it is so hung that it may be spun on the ends of any desired axis1 as1 for instance1 that joining our first color pair1 red and blue-green4 ,with this pair as poles of rotation1 a new equator is traced through all the values of purple on one side and of green-yellow on the other1 which the rotation test melts in a perfect balance of middle gray1 proving the correctness of these values4 ,in the same way it may be hung and tested on successive axes1 until the total balance of the entire spherical series is proved4 7#abc7 ,but this color system does not cease with the colors spread on the surface of a globe4#cj ,the first illustration of an orange filled with color was chosen for the purpose of stimulating the imagination to follow a surface color inward to the neutral axis by regular decrease of chroma4 ,a slice at any level of the solid1 as at value #h 7,fig4 #aj71 shows each hue of that level passing by even steps of increasing grayness to the neutral gray ,n#h of the axis4 ,in the case of red at this level1 it is easily described by the notation ,r #h_/c1 ,r #h_/b1 ,r #h_/a1 of which the initial and upper numerals do not change1 but the lower numeral traces loss of chroma by #c1 #b1 and #a to the neutral axis4 ,footnote #cj3 ,no color is excluded from this system1 but the excess and inequalities of pigment chroma are traced in the ,color ,atlas4 7#abd7 ,and there are stronger chromas of red outside the surface1 which can be written ,r #h_/d1 ,r #h_/e1 ,r #h_/f1 etc4 ,indeed1 our color measurements discover such differences of chroma in the various pigments used1 that the color tree referred to in paragraphs #cd1 #ce1 is necessary to bring before the eye their maximum chromas1 most of which are well outside the spherical shell and at various levels of value4 ,one way to describe the color sphere is to suggest that a color tree1 the intervals between whose irregular branches are filled with appropriate color1 can be placed in a turning lathe and turned down until the color maxima are removed1 thus producing a color solid no larger than the chroma of its weakest pigment 7,fig4 #b74 ,charts of the color solid4 7#abe7 ,thus it becomes evident that1 while the color sphere is a valuable help to the child in conceiving color relations1 in uniting the three scales of color measure1 and in furnishing with its mount an excellent test of the theory of color balance1 yet it is always restricted to the chroma of its weakest color1 the surplus chromas of all other colors being thought of as enormous mountains built out at various levels to reach the maxima of our pigments4 7#abf7 ,the complete color solid is1 therefore1 of irregular shape1 with mountains and valleys1 corresponding to the inequalities of pigments4 ,to display these inequalities to the eye1 we must prepare cross sections or charts of the solid1 some horizontal1 some vertical1 and others oblique4 7#abg7 ,such a set of charts forms an atlas of the color solid1 enabling one to see any color in its relation to all other colors1 and name it by its degree of hue1 value1 and chroma4 ,fig4 #bj is a horizontal chart of all colors which present middle value 7#e71 and describes by an uneven contour the chroma of every hue at this level4 ,the dotted fifth circle is the equator of the color sphere1 whose principal hues1 ,r #e_/e4 ,y #e_/e1 ,g #e_/e1 ,b #e_/e1 and ,p #e_/e1 form the chromatic tuning fork1 paragraph #aag4 ,illustration3 ,fig4 #bj4 ,chart of ,middle ,value - #e - ,showing ,unequal ,chroma in circle of ,hues4 7,see ,fig4 #b74 7#abh7 ,in this single chart the eye readily distinguishes some three hundred different colors1 each of which may be written by its hue1 value1 and chroma4 ,and even the slightest variation of one of them can be defined4 ,thus1 if the principal red were to fade slightly1 so that it was a trifle lighter and a trifle weaker than the enamel1 it would be written ,r#e4a_/d4i1 showing it had lightened by #a per cent4 and weakened by #a per cent4 ,the discrimination made possible by this decimal notation is much finer than our present visual limit4 ,its use will stimulate finer perception of color4 7#abi7 ,such a very elementary sketch of the ,color ,solid and ,color ,atlas1 which is all that can be given in the confines of this small book1 will be elsewhere presented on a larger and more complete scale4 ,it should be contrasted with the ideal form composed of prismatic colors1 suggested in the last chapter1 paragraphs #ih1 #ii1 which was shown to be impracticable1 but whose ideal conditions it follows as far as the limitations of pigments permit4 7#acj7 ,besides its value in education as setting all our color notions in order1 and supplying a simple method for their clear expression1 it promises to do away with much of the misunderstanding that accompanies the every-day use of color4 7#aca7 ,popular color names are incongruous1 irrational1 and often ludicrous4 ,one must smile in reading the list of #be steps in a scale of blue1 made by ,schiffer-,muller in #aggb3-- ,a4 a4 ,white pure4 b4 ,white silvery or pearly4 c4 ,white milky4 ,b4 a4 ,bluish white4 b4 ,pearly white4 c4 ,watery white4 ,c4 ,blue being born4 ,d4 ,blue dying or pale4 ,e4 ,mignon blue4 ,f4 ,celestial blue1 or sky-color4 ,g4 a4 ,azure1 or ultramarine4 b4 ,complete or perfect blue4 c4 ,fine or queen blue4 ,h4 ,covert blue or turquoise4 ,i4 ,king blue 7deep74 ,j4 ,light brown blue or indigo4 ,k4 a4 ,persian blue or woad flower4 b4 ,forge or steel blue4 c4 ,livid blue4 ,l4 a4 ,blackish blue4 b4 ,hellish blue4 c4 ,black-blue4 ,m4 a4 ,blue-black or charcoal4 b4 ,velvet black4 c4 ,jet black4 ,the advantage of spacing these #be colors in #ac groups1 some with three and others with but one example1 is not apparent2 nor why ultramarine should be several steps above turquoise1 for the reverse is generally true4 ,besides which the hue of turquoise is greenish1 while that of ultramarine is purplish1 but the list cannot show this2 and the remarkable statement that one kind of blue is hellish1 while another is celestial1 should rest upon an experience that few can claim4 ,failing to define color-value and color-hue1 the list gives no hint of color-strength1 except at ,c and ,d1 where one kind of blue is dying when the next is being born1 which not inaptly describes the color memory of many a person4 ,finally1 it assures us that ,queen blue is fine and ,king blue is deep4 ,this year the fashionable shades are burnt onion and fresh spinach4 ,the florists talk of a pink violet and a green pink4 ,a maker of inks describes the red as a true crimson scarlet1 which is a contradiction in terms4 ,these and a host of other names borrowed from the most heterogeneous sources1 become outlawed as soon as the simple color terms and measures of this system are adopted4 ,color anarchy is replaced by systematic color description4 ,,appendix ,,to ,,chapter ,v4 ,color schemes based on ,brewster's mistaken theory4 ,illustration ,runge1 of ,hamburg 7#ahaj71 suggested that red1 yellow1 and blue be placed equidistant around the equator of a sphere1 with white and black at opposite poles4 ,as the yellow was very light and the blue very dark1 any coherency in the value scales of red1 yellow1 and blue was impossible4 ,chevreul1 of ,paris 7#ahfa71 seeking uniform color scales for his workmen at the ,gobelins1 devised a hollow cylinder built up of ten color circles4 ,the upper circle had red1 yellow1 and blue spaced equidistant1 and1 as in ,runge's solid1 yellow was very light and blue very dark4 ,each circle was then made one-tenth darker than the next above1 until black was reached at the base4 ,although each circle was supposed to lie horizontally1 only the black lowest circle presents a level of uniform values4 ,yellow values increase their luminosity thrice as fast as purple values1 so that each circle should tilt at an increasing angle1 and the upper circle of strongest colors be inclined at #fj to the black base4 ,besides this fault shared with ,runge's sphere1 it falls into another by not diminishing the size of the lower circles where added black diminishes the chroma4 ,desire to make colors fit a chosen contour1 and the absence of measuring instruments1 cause these schemes to ignore the facts of color relation4 ,like ancient maps made to satisfy a conqueror1 they amuse by their distortion4 ,brewster's mistaken theory underlies these schemes1 as is also the case with ,froebel's gifts1 whose color balls continue to give wrong notions at the very threshold of color education4 ,as pointed out in the ,appendix to ,chapter ,,iii41 the red-yellow-blue theory inevitably spreads the warm field of yellow-red too far1 and contracts the blue field1 so that balance of color is rendered impossible1 as illustrated in the gaudy chromo and flaming bill-board4 ,these schemes are criticised by ,rood as not only in the main arbitrary1 but also vague2 and1 although ,chevreul's charts were published by the government in most elaborate form1 their usefulness is small4 ,interest in the growth of the present system1 because of its measured character1 led ,professor ,rood to give assistance in the tests1 and at his request a color sphere was made for the ,physical ,cabinet at ,columbia4 ,,chapter ,,vi4 ,,color ,,notation4 ,suggestion of a chromatic score4 ,illustration3 ,fig4 #ba4 7#acb7 ,the last chapter traced a series of steps leading to the construction of a practical color sphere4 ,each color was tested by appropriate instruments to assure its degree of hue1 value1 and chroma1 before being placed in position4 ,then the total sphere was tested to detect any lack of balance4 7#acc7 ,each color was also written by a letter and two numerals1 showing its place in the three scales of hue1 value1 and chroma4 ,this naturally suggests1 not only a record of each separate color sensation1 but also a union of these records in series and groups to form a color score1 similar to the musical score by which the measured relations of sound are recorded4 7#acd7 ,a very simple form of color score may be easily imagined as a transparent envelope wrapped around the equator of the sphere1 and forming a vertical cylinder 7,fig4 #ba74 ,on the envelope the equator traces a horizontal centre line1 which is at #e of the value scale1 with zones #f1 #g1 #h1 and #i as parallels above1 and the zones #d1 #c1 #b1 and #a below4 ,vertical lines are drawn through ten equidistant points on this centre line1 corresponding with the divisions of the hue scale1 and marked ,r1 ,,yr1 ,y1 ,,gy1 ,g1 ,,bg1 ,b1 ,,pb1 ,p1 and ,,rp4 7#ace7 ,the transparent envelope is thus divided into one hundred compartments1 which provide for ten steps of value in each of the ten middle colors4 ,now1 if we cut open this envelope along one of the verticals1--as1 for instance1 red-purple 7,,rp71 it may be spread out1 making a flat chart of the color sphere 7,fig4 #bb74 ,why green is given the centre of the score4 7#acf7 ,a cylindrical envelope might be opened on any desired meridian1 but it is an advantage to have green 7,g7 at the centre of the chart1 and it is therefore opened at the opposite point1 red-purple 7,,rp74 ,to the right of the green centre are the meridians of green-yellow 7,,gy71 yellow 7,y71 yellow-red 7,,yr71 and red 7,r71 all of which are known as warm colors1 because they contain yellow and red4 ,to the left are the meridians of blue-green 7,,bg71 blue 7,b71 purple-blue 7,,pb71 and purple 7,p71 all of which are called cool colors1 because they contain blue4 ,green1 being neither warm nor cold of itself1 and becoming so only by additions of yellow or of blue1 thus serves as a balancing point or centre in the hue-scale4#ca ,footnote #ca3 ,to put this in terms of the spectrum wave lengths1 long waves at the red end of the spectrum give the sensation of warmth1 while short waves at the violet end cause the sensation of coolness4 ,midway between these extremes is the wave length of green4 ,illustration3 ,fig4 #bb4 7#acg7 ,the color score presents four large divisions or color fields made by the intersection of the equator with the meridian of green4 ,above the centre are all light colors1 and below it are all dark colors4 ,to the right of the centre are all warm colors1 and to the left are all cool colors4 ,middle green 7#e;,g #e_/e7 is the centre of balance for these contrasted qualities1 recognized by all practical color workers4 ,the chart forms a rectangle whose length equals the equator of the color sphere and its height equals the axis 7a proportion of #c4ad3a71 representing a union and balance of the scales of hue and of value4 ,this provides for two color dimensions2 but1 to be complete1 the chart must provide for the third dimension1 chroma4 7#ach7 ,replacing the chart around the sphere and joining its ends1 so that it re-forms the transparent envelope1 we may thrust a pin through at any point until it pierces the surface of the sphere4 ,indeed1 the pin can be thrust deeper until it reaches the neutral axis1 thus forming a scale of chroma for the color point where it enters 7see paragraph #ab74 ,in the same way any colors on the sphere1 within the sphere1 or without it1 can have pins thrust into the chart to mark their place1 and the length by which each pin projects can be taken as a measure of chroma4 ,if the chart is now unrolled1 it retains the pins1 which by their place describe the hue and value of a color1 while their length describes its chroma4 ,pins stuck into the score represent chroma4 7#aci7 ,with this idea of the third color dimension incorporated in the score we can discard the pin1 and record its length by a numeral4 ,any dot placed on the score marks a certain degree of hue and value1 while a numeral beside it marks the degree of chroma which it carries1 uniting with the hue and value of that point to give us a certain color4 ,glancing over a series of such color points1 the eye easily grasps their individual character1 and connects them into an intelligible series4 7#adj7 ,thus a flat chart becomes the projection of the color solid1 and any color in that solid is transferred to the surface of the chart1 retaining its degrees of hue1 value1 and chroma4 ,so far the scales have been spoken of as divided into ten steps1 but they may be subdivided much finer1 if desired1 by use of the decimal point4 ,it is a question of convenience whether to make a small score with only the large divisions1 or a much larger score with a hundred times as many steps4 ,in the latter case each hue has ten steps1 the middle step of green being distinguished as #e;,g-#e_/e to suggest the four steps #a;,g1 #b;,g1 #c;,g1 #d;,g1 which precede it1 and #f;,g1 #g;,g1 #h;,g1 and #i;,g1 which follow it toward blue-green4 ,illustration3 ,fig4 #bc4 ,,color ,,score--7or ,n #f in ,plate ,,iii7--,,giving ,,areas ,,by ,h1 ,v ,,and ,c4 ,the score preserves color records in a convenient shape4 ,such a color score1 or notation diagram1 to be made small or large as the case demands1 offers a very convenient means for recording color combinations1 when pigments are not at hand4 ,illustration3 ,fig4 #bd4 7#ada7 ,to display its three dimensions1 a little model can be made with three visiting cards1 so placed as to present their mutual intersection at right angles 7,fig4 #bd74 #e;,g #e_/e is their centre of mutual balance4 ,a central plane separates all colors into two contrasted fields4 ,to the right are all warm colors1 to the left are all cool colors4 ,each of these fields is again divided by the plane of the equator into lighter colors above and darker colors below4 ,these four color fields are again subdivided by a transverse plane through #e;,g #e_/e into strong colors in front and weak colors beyond or behind it4 7#adb7 ,any color group1 whose record must all be written to the right of the centre1 is warm1 because red and yellow are dominant4 ,one to the left of the centre must be cool1 because it is dominated by blue4 ,a group written all above the centre must have light in excess1 while one written entirely below is dark to excess4 ,finally1 a score written all in front of the centre represents only strong chromas1 while one written behind it contains only weak chromas4 ,from this we gather that a balanced composition of color preserves some sort of equilibrium1 uniting degrees of warm and cool1 of light and dark1 and of weak and strong1 which is made at once apparent by the dots on the score4 7#adc7 ,a single color1 like that of a violet1 a rose1 or a buttercup1 appears as a dot on the score1 with a numeral added for its chroma4 ,a parti-colored flower1 such as a nasturtium1 is shown by two dots with their chromas1 and a bunch of red and yellow flowers will give by their dots a color passage1 or silhouette1 whose warmth and lightness is unmistakable4 ,the chroma of each flower written with the silhouette completes the record4 ,the hues of a beautiful ,persian rug1 with dark red predominating1 or a verdure tapestry1 in which green is dominant1 or a ,japanese print1 with blue dominant1 will trace upon the score a pattern descriptive of its color qualities4 ,these records1 with practice1 become as significant to the eye as the musical score4 ,the general character of a color combination is apparent at a glance1 while its degrees of chroma are readily joined to fill out the mental image4 7#add7 ,such a plan of color notation grows naturally from the spherical system of measured colors4 ,it is hardly to be hoped1 in devising a color score1 that it should not seem crude at first4 ,but the measures forming the basis of this record can be verified by impartial instruments1 and have a permanent value in the general study of color4 ,they also afford some definite data as to personal bias in color estimates4 7#ade7 ,this makes it possible to collect in a convenient form two contrasting and valuable records1 one preserving such effects of color as are generally called pleasing1 and another of such groups as are found unpleasant to the eye4 ,out of such material something may be gained1 more reliable than the shifting1 personal1 and contradictory statements about color harmony now prevalent4 ,,chapter ,,vii4 ,,color ,,harmony4 ,colors may be grouped to please or to give annoyance4 7#adf7 ,attempts to define the laws of harmonious color have not attained marked success1 and the cause is not far to seek4 ,the very sensations underlying these effects of concord or of discord are themselves undefined4 ,the misleading formula of my student days--that three parts of yellow1 five parts of red1 and eight parts of blue would combine harmoniously--was unable to define the kind of red1 yellow1 and blue intended2 that is1 the hue1 value1 and chroma of each of these colors was unknown1 and the formula meant a different thing to each person who tried to use it4 7#adg7 ,it is true that a certain red1 green1 and blue can be united in such proportions on ,maxwell discs as to balance in a neutral gray2 but the slightest change in either the hue1 value1 or chroma1 of any one of them1 upsets the balance4 ,a new proportion is then needed to regain the neutral mixture4 ,this has already been shown in the discussion of triple balance 7paragraph #hb74 7#adh7 ,harmony of color has been still further complicated by the use of terms that belong to musical harmony4 ,now music is a measured art1 and has found a set of intervals which are defined scientifically4 ,the two arts have many points of similarity2 and the impulses of sound waves on the ear1 like those of light waves on the eye1 are measured vibrations4 ,but they are far apart in their scales1 and differ so much in important particulars that no practical relationship can be set up4 ,the intervals of color sensation require fit names and measures1 ere their infinite variety can be organized into a fixed system4 7#adi7 ,any effort to compare certain sounds to certain colors soon leads to the wildest vagaries4 ,harmony of sound is unlike harmony of color4 7#aej7 ,the poverty of color language tempts to a borrowing from the richer terminology of music4 ,musical terms1 such as pitch1 key1 note1 tone1 chord1 modulation1 nocturne1 and symphony1 are frequently used in the description of color1 serving by association to convey certain vague ideas4 7#aea7 ,in the same way the term color harmony1 from association with musical harmony1 presents to the mind an image of color arrangement1--varied1 yet well proportioned1 grouped in orderly fashion1 and agreeable to the eye4 ,but any attempt to define this image in terms of color is disappointing4 ,here is a beautiful ,persian rug3 why do we call it beautiful8 ,one says because its colors are rich4 ,why are they rich8 ,because they are deep in tone4 ,what does that mean8 ,the double-bass and the fog-horn are deep in tone1 but not necessarily beautiful on that account4 ,oh1 no1 says another1 it is all in one harmonious key4 ,but what is a key of color8 ,is it made by all the values of one color1 such as red1 or by all the hues of equal value1 such as the middle hues in our color solid8 7#aeb7 ,certainly it is neither1 for the rug has both light and dark colors2 and1 of the reds1 yellows1 greens1 and blues1 some are stronger and others weaker4 ,then what do we mean by a key of color8 ,one must either continue to flounder about or frankly confess ignorance4 7#aec7 ,musical harmony explains itself in clear language4 ,it is illustrated by fixed and definite sound intervals1 whose measured relations form the basis of musical composition4 ,each key has an unmistakable character1 and the written score presents a statement that means practically the same thing to every person of musical intelligence4 ,but the adequate terms of color harmony are yet to be worked out4 ,let us leave these musical analogies1 retaining only the clue that a measured and orderly relation underlies the idea of harmony4 ,the color solid which has been the subject of these pages is built upon measured color relations4 ,it unites measured scales of hue1 value1 and chroma1 and gives a definite color name to every sensation from the maxima of color-light and color-strength to their disappearance in darkness4 7#aed7 ,must not this theoretical color solid1 therefore1 locate all the elements which combine to produce color harmony or color discord8#cb ,footnote #cb3 ,professor ,james says there are three classic stages in the career of a theory3 ,first1 it is attacked as absurd2 then admitted to be true1 but obvious and insignificant2 finally it is seen to be so important that its adversaries claim to be its discoverers4 7#aee7 ,instead of theorizing1 let us experiment4 ,as a child at the piano1 who first strikes random and widely separated notes1 but soon seeks for the intervals of a familiar air1 so let us1 after roaming over the color globe and its charts1 select one familiar color1 and study what others will combine with it to please the eye4 7#aef7 ,here is a grayish green stuff for a dress1 and the little girl who is to wear it asks what other colors she may use with it4 ,first let us find it on our instrument1 so as to realize its relation to other degrees of color4 ,its value is #f1--one step above the equator of middle value4 ,its hue is green1 ,g1 and its chroma #e4 ,it is written ,g #f_/e4 7#aeg7 ,color paths lead out from this point in every direction4 ,where shall we find harmonious colors1 where discordant1 where those paths most frequently travelled8 ,are there new ones still to be explored8 7#aeh7 ,there are three typical paths3 one vertical1 with rapid change of value2 another lateral1 with rapid change of hue2 and a third inward1 through the neutral centre to seek the opposite color field4 ,all other paths are combinations of two or three of these typical directions in the color solid4 ,three typical color paths4 ,illustration3 ,fig4 #be4 7#aei7 #a4 ,the vertical path finds only lighter and darker values of gray-green1--self-colors or shades1 they are generally called1--and offers a safe path1 even for those deficient in color sensation1 avoiding all complications of hue1 and leaving the eye free to estimate different degrees of a single quality1--color-light4 7#afj7 #b4 ,the lateral path passes through neighboring hues on either side4 ,in this case it is a sequence from blue1 through green into yellow4 ,this is simply change of hue1 without change of value or chroma if the path be level1 but1 by inclining it1 one end of the sequence becomes lighter1 while the other end darkens4 ,it thus becomes an intermediate between the first and second typical paths1 combining1 at each step1 a change of hue with a change of value4 ,this is more complicated1 but also more interesting1 showing how the character of the gray-green dress will be set off by a lighter hat of ,leghorn straw1 and further improved by a trimming of darker blue-green4 ,the sequence can be made still more subtle and attractive by choosing a straw whose yellow is stronger than the green of the dress1 while a weaker chroma of blue-green is used in the trimming4 ,this is clearly expressed by the notation thus3 ,y #h_/g1 ,g #f_/e1 ,,bg #d_/c1 and written on the score by three dots and their chromas1--#g1 #e1 and #c 7see ,fig4 #bc74 7#afa7 #c4 ,the inward path which leads by increase of gray to the neutral centre1 and on to the opposite hue red-purple1 ,,rp #d_/e1 is full of pitfalls for the inexpert4 ,it combines great change of hue and chroma1 with small change of value4 7#afb7 ,if any other color point be chosen in place of gray-green1 the same typical paths are just as easily traced1 written by the notation1 and recorded on the color score4 ,these paths trace sequences from any point in the color solid4 7#afc7 ,in the construction of the color solid we saw that its scales were made of equal steps in hue1 value1 and chroma1 and tested by balance on the centre of neutral gray4 ,any step will serve as a point of departure to trace regular sequences of the three types4 ,the vertical type is a sequence of value only4 ,it is somewhat tame1 lacking the change of hue and chroma1 but giving a monotonous harmony of regular values4 ,the horizontal type traces a sequence of neighboring hues1 less tame than the vertical type1 but monotonous in value and chroma4 ,the inward type connects opposite hues by a sequence of chroma balanced on middle gray1 and is more stimulating to the eyes4 7#afd7 ,these paths have so far been treated as made up of equal steps in each direction1 with the accompanying idea of equal quantities of color at each step4 ,but by using unequal quantities of color1 the balance may be preserved by compensations to the intervals that separate the colors 7see paragraphs #aji1 #aaj74 ,unequal color quantities compensated by relations of hue1 value1 and chroma4 7#afe7 ,small bits of powerful color can be used to balance large fields of weak chroma4 ,for instance1 a spot of strong reddish purple is balanced and enhanced by a field of gray-green4 ,so an amethyst pin at the neck of the girl's dress will appear to advantage with the gown1 and also with the ,leghorn straw4 ,but a large field of strong color1 such as a cloth jacket of reddish purple1 would be fatal to the measured harmony we seek4 7#aff7 ,this use of a small point of strong chroma1 if repeated at intervals1 sets up a notion of rhythm2 but1 in order to be rhythmic1 there must be recurrent emphasis1 a succession of similar units1 combining unlike elements4 ,this quality must not be confused with the unaccented succession1 seen in a measured scale of hue1 value1 or chroma4 ,paper masks to isolate color intervals4 7#afg7 ,a sheet of paper large enough to hide the color sphere may be perforated with three or more openings in a straight line1 and applied against the surface1 so as to isolate the steps of any sequence which we wish to study4 ,thus the sequence given in paragraph #afj--,y #h_/g1 ,g #f_/e1 ,,bg #d_/c--may be changed to bring it on the surface of the sphere1 when it reads ,y #h_/c1 ,g #f_/e1 ,,bg #e_/e4 ,a mask with round holes1 spaced so as to uncover these three spots1 relieves the eye from the distraction of other colors4 ,keeping the centre spot on green1 the mask may be moved so as to study the effect of changing hue or value of the other two steps in the sequence4 7#afh7 ,the sequence is lightened by sliding the whole mask upward1 and darkened by dropping it lower4 ,then the result of using the same intervals in another field is easily studied by moving the mask to another part of the solid4 7#afi7 ,change of interval immediately modifies the character of a color sequence4 ,this is readily shown by having an under-mask1 with a long1 continuous slit1 and an over-mask whose perforations are arranged in several rows1 each row giving different spaces between the perforations4 ,in the case of the girl's clothing1 the same sequence produces quite a different effect1 if two perforations of the over-mask are brought nearer to select a lighter yellow-green dress1 while the ends of the sequence remain unchanged4 ,to move the middle perforation near the other end1 selects a darker bluish green dress1 on which the trimming will be less contrasted1 while the hat appears brighter than before1 because of greater contrast4 7#agj7 ,the variations of color sequence which can thus be studied out by simple masks are almost endless2 yet upon a measured system the character of each effect is easily described1 and1 if need be1 preserved by a written record4 ,invention of color groups4 7#aga7 ,experiments with variable masks for the selection of color intervals1 such as have been described1 soon stimulate the imagination1 so that it conceives sequences through any part of the color solid4 ,the color image becomes a permanent mental adjunct4 ,five middle colors1 tempered with white and black1 permit us to devise the greatest variety of sequences1 some light1 others dark1 some combining small difference of chroma with large difference of hue1 others uniting large intervals of chroma with small intervals of hue1 and so on through a well-nigh inexhaustible series4 7#agb7 ,as this constructive imagination gains power1 the solid and its charts may be laid aside4 ,we can now think color consecutively4 ,each color suggests its place in the system1 and may be taken as a point of departure for the invention of groups to carry out a desired relation4 7#agc7 ,this selective mental process is helped by the score described in the last chapter2 and the quantity of each color chosen for the group is easily indicated by a variable circle1 drawn round the various points on the diagram4 ,thus1 in the case of the child's clothes1 a large circle around ,g #f_/e gives the area of that color as compared with smaller circles around ,y #h_/g and ,,bg #d_/c1 representing the area of the straw and the trimming4 7#agd7 ,when the plotting of color groups has become instinctive from long practice1 it opens a wide field of color study4 ,take as illustration the wings of butterflies or the many varieties of pansies4 ,these fascinating color schemes can be written with indications of area that record their differences by a simple diagram4 ,in the same way1 rugs1 tapestries1 mosaics1--whatever attracts by its beauty and harmony of color1--can be recorded and studied in measured terms2 and the mental process of estimating hues1 values1 chromas1 and areas by established scales must lead the color sense to finer and finer perceptions4 ,the same process serves as well to record the most annoying and inharmonious color groups4 ,when sufficient of these records have been obtained1 they furnish definite material for a contrast of the color combinations which please1 with those that cause disgust4 ,such a contrast should discover some broad law of color harmony4 ,it will then be in measured terms which can be clearly given2 not a vague personal statement1 conveying different meanings to each one who hears it4 ,constant exercise needed to train the color sense4 7#age7 ,appreciation of beautiful color grows by exercise and discrimination1 just as naturally as fine perception of music or literature4 ,each is an outlet for the expression of taste1--a language which may be used clumsily or with skill4 7#agf7 ,as color perception becomes finer1 it discards the more crude and violent contrasts4 ,a child revels in strong chromas1 but the mark of a colorist is ability to employ low chroma without impoverishing the color effect4 ,as a boy's shrieks and groans can be tempered to musical utterance1 so his debauches in violent red1 green1 and purple must be replaced by tempered hues4 7#agg7 ,raphael1 ,titian1 ,velasquez1 ,corot1 ,chavannes1 and ,whistler are masters in the use of gray4 ,personal bias may lead one colorist a little more toward warm colors1 and another slightly toward the cool field1 in each case attaining a sense of harmonious balance by tempered degrees of value and chroma4#cc ,footnote #cc3 ,nature's most lively hues are bathed in lilac grays4 ,spread all about us1 yet visible only to the fine perception of the colorist1 is this gray quality by which he appeals4 ,not he whose pictures abound in 'couleurs voyantes1' but he who preserves in his work all the 'gris colors' is the good colorist4 ,translation from ,j4 ,f4 ,rafaelli1 in ,annales ,politiques ,litteraires4 7#agh7 ,it is not claimed that discipline in the use of subtle colors will make another ,corot or ,velasquez1 but it will make for comprehension of their skill4 ,it is grotesque to watch gaudily dressed persons going into ecstasies over the delicate coloring of a ,botticelli1 when the internal as well as the external evidence is against them4 7#agi7 ,the colors which we choose1 not only in personal apparel1 but in our rooms and decorations1 are mute witnesses to a stage of color perception4 ,if that perception is trained to finer distinctions1 the mind can no longer be content with coarse expression4 ,it begins to feel an incongruity between the loud color of the wall paper1 bought because it was fashionable1 and the quiet hues of the rug1 which was a gift from some artistic friend4 ,it sees that1 although the furniture is covered with durable and costly materials1 their color swears at that of the curtains and wood-work4 ,in short1 the room has been jumbled together at various periods1 without any plan or sense of color design4 7#ahj7 ,good taste demands that a room be furnished1 not alone for convenience and comfort1 but also with an eye to the beauty of the various objects1 so that1 instead of confusing and destroying the colors1 each may enhance the other4 ,and1 when this sense of color harmony is aroused1 it selects and arranges the books1 the rugs1 the lamp shade1 the souvenirs of travel and friendship1 the wall paper1 pictures1 and hangings1 so that they fit into a color scheme1 not only charming to the eye at first glance1 but which continues to please the mind as it traces out an intelligent plan1 bringing all into general harmony4 7#aha7 ,nor will this cease when one room has been put to rights4 ,such a coloristic attitude is not satisfied until the vista into the next apartment is made attractive4 ,or should there be a suite of rooms1 it demands that1 with variety in each one1 they all be brought into harmonious sequence4 ,thus the study of color finds immediate and practical use in daily life4 ,it is a needed discipline of color vision1 in the sense that geometry is a discipline of the mind1 and it also enters into the pleasure and refinement of life at every step4 ,skill or awkwardness in its use exerts as positive an influence upon us as do the harmonies and discords of sound1 and a far more continuous one4 ,it is thought a defect to be unmusical4 ,should it not be considered a mark of defective cultivation to be insensitive to color8 7#ahb7 ,in this slight sketch of color education it has been assumed that we are to deal with those who have normal perceptions4 ,but there are some who inherit or develop various degrees of color-blindness2 and a word in their behalf may be opportune4 7#ahc7 ,a case of total color-blindness is very rare1 but a few are on record4 ,when a child shows deficient color perception1#cd a little care may save him much discomfort1 and patient training may correct it4 ,if he mismatches some hues1 confuses their names1 seems incapable of the finer distinctions of color1 study to find the hues which he estimates well1 and then help him to venture a little into that field where his perception is at fault4 ,improvement is pretty sure to follow when this is sympathetically done4 ,one student1 who never outgrew the habit of giving a purplish hue to all his work1 despite many expedients and the use of various lights and colored objects to correct it1 is the single exception among hundreds whom it has been my privilege to watch as they improved their first crude estimates1 and gained skill in expressing their sense of ,nature's subtle color4 ,footnote #cd3 ,see ,color ,blindness in ,glossary4 7#ahd7 ,to sum up1 the first chapter suggests a measured color system in place of guess-work4 ,the next describes the three color qualities1 and sketches a child's growth in color perception4 ,the third tells how colors may be mingled in such proportions as to balance4 ,after the impracticability of using spectral color has been shown in the fourth chapter1 the fifth proceeds to build a practical color solid4 ,the sixth provides for a written record of color1 and the last applies all that has preceded to suggestions for the study of color harmony4 7#ahe7 ,wide gaps appear in this outline4 ,there is much that deserves fuller treatment4 ,but1 if the search for refined color and a clearer outlook upon its relations are stimulated by this fragmentary sketch1 some of its faults may be overlooked4 ,illustration3 ,,reproduction ,,of ,,flower ,,studies1 ,,painted ,,with ,,munsell ,,water ,,color ,published ,by ,,wadsworth1 ,,howland ,,co41 ,,incorporated ,,boston1 ,,mass4 ,,part ,,ii4 ,a ,,color ,,system ,,and ,,course ,,of ,,study ,,based ,,on ,,the ,,color ,,solid ,,and ,,its ,,charts4 ,arranged for nine years of school life4 ,,glossary ,,of ,,color ,,terms4 ,taken from the ,century ,dictionary4 ,,index 7by paragraphs74 ,illustration3 ,fig4 #b 7,see ,fig4 #bj7 ,the ,color ,tree ,a ,,color ,,system ,,with ,,course ,,of ,,study ,,based ,,on ,,the ,,color ,,solid ,,and ,,its ,,charts ,see ,chapter ,,ii4 ,copyright1 #aijd1 by ,a4 ,h4 ,munsell4 ,a ,,color ,,system ,,and ,,course ,,of ,,study ,,based ,,on ,,the ,,color ,,solid ,,and ,,its ,,charts1 ,,adapted ,,to ,,nine ,,years ,,of ,,school ,,life4 ,gr4 ,grade ,ill4 ,illustration ,app4 ,application ,mat4 ,materials ,gr4 ,subject4 ,colors ,studied4 ,ill4 ,app4 ,mat4 ---------------------------------------- ----------------------- #a4 ,,hues ,red4 ,r4 ,sought in ,borders ,colored of ,yellow4 ,y4 ,nature and crayons color4 ,green4 ,g4 and ,art4 ,rosettes4 and ,blue4 ,b4 papers4 ,purple4 ,p4 ---------------------------------------- ----------------------- #b4 ,,hues ,yellow-red4 ,,yr4 ,sought in ,borders ,colored of ,green-yellow4 ,,gy4 ,nature and crayons color4 ,blue-green4 ,,bg4 and ,art4 ,rosettes4 and ,purple-blue4 ,,pb4 papers4 ,red-purple4 ,,rp4 ---------------------------------------- ----------------------- #c4 ,,values ,light1 middle1 ,sought in ,design4 ,color of and dark ,r4 ,nature sphere4 color4 ,y4 and ,art4 ,g4 ,b4 ,p4 ---------------------------------------- ----------------------- #d4 ,,values #e values of ,,yr4 ,sought in ,design4 ,charts4 of ,,gy4 ,nature color4 ,,bg4 and ,art4 ,,pb4 ,,rp4 #i_/1 #g_/1 #e_/1 #c_/1 #a_/4 ---------------------------------------- ----------------------- #e4 ,,chromas #c chromas of ,r#e_/4 ,sought in ,design4 ,charts4 of ,y#e_/4 ,nature color4 ,g#e_/4 and ,art ,b#e_/4 ,p#e_/4 ---------------------------------------- ----------------------- #f4 ,,chromas #c chromas of ,,yr#e_/4 ,sought in ,design ,color of ,,gy#e_/4 ,nature ,tree4 color4 ,,bg#e_/4 and ,art4 ,,pb#e_/4 ,,rp#e_/4 ,r#g_/ and ,r#c_/4 ,y#g_/ ,y#c_/4 ,g#g_/ ,g#c_/4 ,b#g_/ ,b#c_/4 ,p#g_/ ,p#c_/4 ---------------------------------------- ----------------------- #g4 ,to ,,observe ,,imitate ,,write color by ,,hue1 ,,value1 and ,,chroma ,paints4 ---------------------------------------- --------------------------- #h4 ,,quantity of color4 ,pairs of equal area and unequal area ,paints4 ,balanced by ,,hue1 ,,value1 and ,,chroma4 ---------------------------------------- --------------------------- #i4 ,,quantity of color4 ,triads of equal area and unequal area ,paints4 ,balanced by ,,hue1 ,,value1 and ,,chroma4 ,copyright1 #aijd1 by ,a4 ,h4 ,munsell4 ,,study ,,of ,,single ,,hues ,,and ,,their ,,sequence4 ,two ,years4 ,,first ,,grade ,,lessons4 #a4 ,talk about familiar objects1 to bring out color names1 #b4 as toys1 flowers1 clothing1 birds1 insects1 etc4 #c4 ,show soap bubbles and prismatic spectrum4 #d4 ,teach term ,,hue4 ,hues of flowers1 spectrum1 plumage of birds1 etc4 #e4 ,show ,,middle#ce ,,red4 ,find other reds4 #f4 ,show ,,middle ,,yellow4 ,find other yellows1 and compare with reds4 #g4 ,show ,,middle ,,green4 ,find other greens1 with reds and yellows4 #h4 ,show ,,middle ,,blue4 ,find other blues1 with preceding hues4 #i4 ,show ,,middle ,,purple4 ,find other purples1 with preceding hues4 #aj-ae4 ,review ,,five ,,middle ,,hues1#ce match with colored papers1 and place in circle4 #af-bj4 ,show ,,color ,,sphere4 ,find sequence of five middle hues4 ,memorize order4 #ba4 ,middle red imitated with crayon1 named and written by initial ,r4 #bb4 ,middle yellow by initial ,y4 #bc4 ,middle green by initial ,g4 #bd4 ,middle blue by initial ,b4 #be4 ,middle purple by initial ,p4 #bf-cj4 ,review1 using middle hues#ce in borders and rosettes for design4 ,aim4--,to recognize sequence of five middle hues4 ,to name1 match1 imitate1 write1 and arrange them4 ,,second ,,grade ,,lessons4 #a-c4 ,review sequence of five middle hues4#ce #d4 ,show a hue ,,intermediate between red and yellow4 ,find it in objects4 #e4 ,compare with red and yellow4 #f4 ,recognize and name ,,yellow-,,red4 ,match1 imitate1 and write ,,yr4 #g-h4 ,show ,,green-,,yellow between green and yellow4 ,treat as above1 and write ,,gy4 #i-aj4 ,show ,,blue-,,green between blue and green4 and write ,,bg4 #aa-ab4 ,show ,,purple-,,blue between purple and blue4 and write ,,pb4 #ac-ad4 ,show ,,red-,,purple between red and purple4 and write ,,rp4 #ae-bj4 ,make circle of ten hues4 ,place ,intermediates1 and memorize order so as to repeat forward or backward4 ,match1 imitate1 and write by initials4 #ba-be4 ,find sequence of ten hues on ,,color ,,sphere4 ,compare with hues of natural objects4 #bf-cj4 ,review1 using any two hues in sequence for borders and rosettes4 ,aim4--,to recognize sequence of ten hues1 made up of five middle#ce hues and the five intermediates4 ,to name1 match1 write1 imitate1 and arrange them4 ,footnote #ce3 ,the term ,,middle1 as used in this course of color study1 is understood to mean only the five principal hues which stand midway in the scales of ,,value and ,,chroma4 ,strictly speaking1 their five intermediates are also midway of the scales2 but they are obtained by mixture of the five principal hues1 as shown in their names1 and are of secondary importance4 ,,study ,,of ,,single ,,values ,,and ,,their ,,sequence4 ,two ,years4 ,,third ,,grade ,,lessons4 #a4 ,review sequence of ten hues4 #b4 ,recognize1 name1 match1 imitate1 write1 and find them #c4 on the ,,color ,,sphere4 ,also in objects4 #d4 ,teach use of term ,,value4 ,color value recognized apart from color hue4 #e4 ,find values of red1 lighter and darker than the middle value already familiar4 #g4 ,,three ,,values of ,,red4 ,find on sphere4 ,name as ,,light1 ,,middle1 and ,,dark values of red4 #h4 ,,three ,,values of ,,red4 ,imitate with crayons1 and write them as #c1 #e1 and #g4 #i4 ,,three ,,values of ,,yellow4 ,compare with above4 #aj4 ,recognize1 name1 match1 and imitate with crayons4 #aa4 ,,three ,,values of ,,green4 ,compare1 and treat as above4 #ab4 ,find on sphere and in objects4 #ac4 ,,three ,,values of ,,blue4 #ad4 #ae4 ,,three ,,values of ,,purple4 #af4 #ag-bj4 ,review1 combining two values and a single hue for design4#cf ,aim4--,to recognize a sequence combining three values and five middle hues4 ,to name1 match1 imitate1 and arrange them4 ,footnote #cf3 ,these ten lessons in this and succeeding grades are devoted to color perception only4 ,their application to design is a part of the general course in drawing1 and will be so considered in the succeeding grades4 ,note that1 although thus far nothing has been said about complementary hues1 the child has been led to associate them in opposite pairs by the color sphere4 7,see ,chapter ,,iii41 p4 #gf47 ,error for paragraph #gf ,,fourth ,,grade ,,lessons4 #a4 ,review sequence of three values in each of the five middle hues4 #b4 ,to recognize1 name1 match1 imitate1 and #c4 find them on sphere and in objects4 #d4 ,show ,,five ,,values of ,,red4 ,find them on large color sphere4 #e4 ,number them #a1 #c1 #e1 #g1 #i4 ,match1 imitate1 and write4 #f4 ,show ,,five ,,values of ,,blue-,,green4 ,treat as above and review4 #g4 ,show ,,five ,,values of ,,purple-,,blue compared with ,yellow4 ,treat as above and review4 #h4 ,show ,,five ,,values of ,,red-,,purple ,green4 ,treat as above and review4 #i4 ,show ,,five ,,values of ,,yellow-,,red ,blue4 ,treat as above and review4 #aj4 ,show ,,five ,,values of ,,green-,,yellow ,purple4 ,treat as above and review4 ,aim4--,to recognize sequences combining five values in each of ten hues4 ,to name1 match1 imitate1 ,,write1 and arrange them4 ,,study ,,of ,,single ,,chromas ,,and ,,their ,,sequences4 ,two ,years4 ,,fifth ,,grade ,,lessons4 #a4 ,review sequences of hue and value4 ,find them on the color sphere4 ,name1 match1 imitate1 write1 and arrange them by hue and value4 #b4 ,teach use of term ,,chroma4 ,compare three chromas with three values of red4 ,name them ,,weak1 ,,middle1 and ,,strong chromas4 ,find in nature and art4 #c4 ,,three ,,chromas of ,,red4 ,compare with three of blue-green4 #d4 ,show ,,color ,,tree4 ,suggest unequal chroma of hues4 #e4 ,,three ,,chromas of ,,yellow4 ,compare with three chromas of purple-blue4 #f4 ,,three ,,chromas of ,,green4 red-purple4 #g4 ,,three ,,chromas of ,,blue4 yellow-red4 #h4 ,,three ,,chromas of ,,purple4 green-yellow4 #i4 ,arrange five middle hues in circle1 described as on the surface of the ,color ,sphere 7middle chroma71 with weaker chromas inside1 and stronger chromas outside1 the sphere4 #aj4 ,review1--to find these sequences of chroma in nature and art4 ,aim4--,to recognize sequences combining three chromas1 middle value1 and ten hues4 ,to name1 match1 imitate1 and arrange them4 ,,sixth ,,grade ,,lessons4 #a4 ,review sequences combining three chromas1 five hues1 and middle value4 ,find on ,color ,tree1 name1 match1 imitate1 and arrange them4 #b4 ,,three ,,chromas of ,,lighter and ,,darker ,,red4 ,compare with middle red4 #c4 ,write as a fraction1 chroma under value1 using #c1 #e1 and #g4 ,thus ,r #e_/g4 #d4 ,find ,,chromas of ,,lighter ,,red1 and compare with darker blue-green4 #e4 ,,three ,,chromas of ,,lighter and ,,darker ,,yellow1 with purple-blue4 #f4 ,,green1 red-purple4 #g4 ,,blue1 yellow-red4 #h4 ,,purple1 green-yellow4 #i4 ,colors in nature and art1 defined by hue1 value1 and chroma4 ,named1 matched1 imitated1 written1 and arranged by ,color ,sphere and ,tree4 #aj4 ,review1--to find sequences combining three chromas1 five values1 and ten hues4 ,aim4--,to recognize sequences of chroma1 as separate from sequences of hue or sequences of value4 ,to name1 match1 write1 imitate1 and arrange colors in terms of their hue1 value1 and chroma4 ,,color ,,expression ,,in ,,terms ,,of ,,the ,,hues1 ,,values1 ,,and ,,chromas4 ,,seventh ,,grade ,,lessons4 #a4 ,review sequences of hue 7initial71 value 7upper numeral71 chroma 7lower numeral74 #b4 #c4 ,exercises in expressing colors of natural objects by the ,,notation1 #d4 and tracing their relation by the spherical solid4 #e4 ,,reds in ,nature and ,art1 imitated1 written1 and traced by the spherical solid4 #f4 ,,yellows in ,nature and ,art1 by the spherical solid4 #g4 ,,greens in ,nature and ,art1 by the spherical solid4 #h4 ,,blues in ,nature and ,art1 by the spherical solid4 #i4 ,,purples in ,nature and ,art1 by the spherical solid4 #aj4 ,,one ,,color ,,pair selected1 defined1 and arranged for design4 7,see note #dth ,grade47 ,aim4--,to define any color by its hue1 value1 and chroma4 ,to imitate with pigments and write it4 ,,eighth ,,grade ,,lessons4 #a4 ,review sequences1 and select colors which balance4 ,illustrate the term4 #b4 ,,balance of light and dark1--weak and strong1--hot and cold colors4 #c4 ,,red and blue-green balanced in hue1 value1 and chroma1 with ,,equal ,,areas4 #d4 ,,yellow and purple-blue with ,,equal ,,areas4 #e4 ,,green and red-purple with ,,equal ,,areas4 #f4 ,,blue and yellow-red with ,,equal ,,areas4 #g4 ,,purple and green-yellow with ,,equal ,,areas4 #h4 ,,unequal ,,areas of the above pairs1 balanced by compensating #i4 qualities of hue1 value1 and chroma4 ,examples from nature and art4 #aj4 ,,one ,,color ,,pair of unequal areas selected1 defined1 and used in design4 ,aim4--,to ,,balance colors by area1 hue1 value1 and chroma4 ,to imitate with pigments and write the balance by the notation4 ,,ninth ,,grade ,,lessons4 #a4 ,review balance of color pairs1 by area1 hue1 value1 and chroma4 #b4 ,to recognize1 name1 imitate1 write1 and record them4 #c4 ,,selection of two colors to balance a given ,,red4 #d4 ,,yellow4 #e4 ,,green4 #f4 ,,blue4 #g4 ,,purple4 #h-aj4 ,,triad of color1 selected1 balanced1 written1 and used in design4 ,aim4--,to recognize triple balance of color1 and express it in terms of area1 hue1 value1 and chroma4 ,also to use it in design4 ,,glossary ,,of ,,color ,,terms ,,taken ,,from ,,the ,,century ,,dictionary4 ,,glossary ,the color definitions here employed are taken from the ,century ,dictionary4 ,special attention is called to the cross references which serve to differentiate ,,hue1 ,,value1 and ,,chroma4 ,,after ,,image4--,an image perceived after withdrawing the eye from a brilliantly illuminated object4 ,such images are called positive when their colors are the same as that of the object1 and negative when they are its complementary colors4 ,,blue4--,of the color of the clear sky2 of the color of the spectrum between wave lengths 4#eje and 4#dae micron1 and more especially 4#dhg and 4#dfj2 or of such light mixed with white2 azure1 cerulean4 ,,black4--,possessing in the highest degree the property of absorbing light2 reflecting and transmitting little or no light2 of the color of soot or coal2 of the darkest possible hue2 sable4 ,optically1 wholly destitute of color1 or absolutely dark1 whether from the absence or the total absorption of light4 ,opposed to white4 ,,brown4--,a dark color1 inclined to red or yellow1 obtained by mixing red1 black1 and yellow4 ,,chroma4--,the degree of departure of a color sensation from that of white or gray2 the intensity of distinctive hue2 color intensity4 ,,chromatic4--,relating to or of the nature of color4 ,,cobalt ,,blue4--,a pure blue tending toward cyan blue and of high luminosity2 also called ,hungary blue1 ,lethner's blue1 and ,paris blue4 ,,color4--,objectively1 that quality of a thing or appearance which is perceived by the eye alone1 independently of the form of the thing2 subjectively1 a sensation peculiar to the organ of vision1 and arising from the optic nerve4 ,,color ,,blindness4--,incapacity for perceiving colors1 independent of the capacity for distinguishing light and shade4 ,the most common form is inability to perceive red as a distinct color1 red objects being confounded with gray or green2 and next in frequency is the inability to perceive green4 ,,color ,,constants4--,the numbers which measure the quantities1 as well as any other system of three numbers for defining colors1 are called constants of color4 ,,color ,,variables4--,colors vary in ,,chroma1 or freedom from admixture of white light2 in ,,brightness1 or luminosity2 and in ,,hue1 which roughly corresponds to the mean wave length of the light emitted4 ,,colors1 ,,complementary4--,those pairs of color which when mixed produce white or gray light1 such as red and green-blue1 yellow and indigo-blue1 green-yellow and violet4 ,,colors1 ,,primary4--,the red1 green1 and violet light of the spectrum1 from the mixture of which all other colors can be produced4 ,also called fundamental colors4 ,,dyestuffs4--,in commerce1 any dyewood1 lichen1 or dyecake used in dyeing and staining4 ,,electric ,,light4--,light produced by electricity and of two general kinds1 the arc light and the incandescent light4 ,in the first the voltaic arc is employed4 ,in the second a resisting conductor is rendered incandescent by the current4 ,,enamel4--,in the fine arts a vitreous substance or glass1 opaque or transparent1 and variously colored1 applied as a coating on a surface of metal or of porcelain4 ,,grating1 ,,diffraction4--,a series of fine parallel lines on a surface of glass1 or polished metal1 ruled very close together1 at the rate of #aj1jjj to #bj1jjj or even #dj1jjj to the inch2 distinctively called a diffraction or a diffraction grating1 much used in spectroscopic work4 ,,gray4--,a color having little or no distinctive hue 7,,chroma7 and only moderate luminosity4 ,,green4--,the color of ordinary foliage2 the color seen in the solar spectrum between wave lengths #j4eaa and #j4edc micron4 ,,emerald ,,green4--,a highly chromatic and extraordinarily luminous green of the color of the spectrum at wave length #j4ebd micron4 ,it recalls the emerald by its brilliancy1 but not by its tint2 applied generally to the aceto-arsenate of copper4 ,usually known as ,paris green4 ,,high ,,color4--,a hue which excites intensely chromatic color sensations4 ,,hue4--,specifically and technically1 distinctive quality of coloring in an object or on a surface2 the respect in which red1 yellow1 green1 blue1 etc41 differ one from another2 that in which colors of equal luminosity and ,,chroma may differ4 ,,indigo4--,the violet-blue color of the spectrum1 extending1 according to ,helmholtz1 from ,g two-thirds of the way to ,f in the prismatic spectrum4 ,the name was introduced by ,newton1 but has lately been discarded by the best writers4 ,,light4--,adjective applied to colors highly luminous and more or less deficient in ,,chroma4 ,,luminosity4--,specifically1 the intensity of light in a color1 measured photometrically2 that is to say1 a standard light has its intensity1 or vis viva1 altered1 until it produces the impression of being equally bright with the color whose light is to be determined2 and the measure of the vis viva of the altered light1 relatively to its standard intensity1 is then taken as the luminosity of the color in question4 ,,maxwell ,,color ,,discs4--,discs having each a single color1 and slit radially so that one may be made to lap over another to any desired extent4 ,by rotating these on a spindle1 the effect of combining certain colors in varying proportions can be studied4 ,,micron4--,the millionth part of a metre1 or #a_/bcdjj of an ,english inch4 ,the term has been formally adopted by the ,international ,commission of ,weights and ,measures1 representing the civilized nations of the world1 and is adopted by all metrologists4 ,,orange4--,a reddish yellow color1 of which the orange is the type4 ,,vision1 ,,persistence ,,of4--,the continuance of a visual impression upon the retina of the eye after the exciting cause is removed4 ,the length of time varies with the intensity of the light and the excitability of the retina1 and ordinarily is brief1 though the duration may be for hours1 or even days4 ,the after image may be either positive or negative1 the latter when the bright part appears dark and the colored parts in their corresponding contrast colors4 ,it is because of this persistence that1 for example1 a firebrand moved very rapidly appears as a band or circle of light4 ,,photometer4--,an instrument used to measure the intensity of light4 ,specifically1 to compare the relative intensities of the light emitted from various sources4 ,,pigment4--,any substance that is or can be used by painters to impart color to bodies4 ,,pink4--,a red color of low chroma1 but high luminosity1 inclining toward purple4 ,,primary ,,colors4--,see ,colors1 primary4 ,,pure ,,color4--,a color produced by homogeneous light4 ,any very brilliant or decided color4 ,,purple4--,a color formed by the mixture of blue and red1 including the violet of the spectrum above wave length #j4dag1 which is nearly a violet blue1 and extending to1 but not including1 crimson4 ,,rainbow4--,a bow or an arc of a circle1 consisting of the prismatic colors1 formed by the refraction and the reflection of rays of light from drops of rain or vapor1 appearing in the part of the heavens opposite to the sun4 ,,red4--,a color more or less resembling that of blood1 or the lower end of the spectrum4 ,red is one of the most general color names1 and embraces colors ranging in hue from aniline to scarlet iodide of mercury and red lead4 ,a red yellower than vermilion is called scarlet4 ,one much more crimson is called crimson red4 ,a very dark red1 if pure or crimson1 is called maroon2 if brownish1 chestnut or chocolate4 ,a pale red--that is1 one of low ,,chroma and high ,,luminosity--is called a pink1 ranging from rose pink or pale crimson to salmon pink or pale scarlet4 ,,venetian ,,red4--,an important pigment used by artists1 somewhat darker than brick red in color1 and very permanent4 ,,retina4--,the innermost and chiefly nervous coat of the posterior part of the eyeball4 ,,saturation1 ,,of ,,colors4--,in optics the degree of admixture with white1 the saturation diminishing as the amount of white is increased4 ,in other words1 the highest degree of saturation belongs to a given color when in the state of greatest purity4 ,,scale4--,a graded system1 by reference to which the degree1 intensity1 or quality of a sense perception may be estimated4 ,,shade4--,degree or gradation of defective luminosity in a color1 often used vaguely from the fact that paleness1 or high luminosity1 combined with defective ,,chroma1 is confounded with high luminosity by itself4 ,see ,color1 ,hue1 and ,tint4 ,,spectrum4--,in physics the continuous band of light showing the successive prismatic colors1 or the isolated lines or bands of color1 observed when the radiation from such a source as the sun or an ignited vapor in a gas flame is viewed after having been passed through a prism 7prismatic spectrum7 or reflected from a diffraction grating 7diffraction or interference spectrum74 ,see ,rainbow4 ,,tint4--,a variety of color2 especially and properly1 a luminous variety of low ,,chroma2 also1 abstractly1 the respect in which a color may be raised by more or less admixture of white1 which at once increases the luminosity and diminishes the ,,chroma4 ,,tone4--,a sound having definiteness and continuity enough so that its pitch1 force1 and quality may be readily estimated by the ear4 ,musical sound opposed to noise4 ,the prevailing effect of a color4 ,,ultramarine4--,a beautiful natural blue pigment1 obtained from the mineral lapis-lazuli4 ,,value4--,in painting and the allied arts1 relation of one object1 part1 or atmospheric plane of a picture to the others1 with reference to light and shade1 the idea of ,,hue being abstracted4 ,,vermilion4--,the red sulphate of mercury4 ,,violet4--,a general class of colors1 of which the violet flower is a highly chromatic example4 ,the sensation is produced by a pure blue whose ,,chroma has been diminished while its ,,luminosity has been increased4 ,thus blue and violet are the same color1 though the sensations are different4 ,a mere increase of illumination may cause a violet blue to appear violet1 with a diminution of apparent ,,chroma4 ,this color1 called violet or blue according to the quality of the sensation it excites1 is one of the three fundamental colors of ,young's theory4 ,a deep blue tinged with red4 ,,viridian4--,same as ,veronese green4 ,,white4--,a color transmitting1 and so reflecting to the eye1 all the rays of the spectrum1 combined in the same proportion as in the impinging light4 ,,yellow4--,the color of gold and of light1 of wave length #j4eha micron4 ,the name is restricted to highly chromatic and luminous colors4 ,when reduced in ,,chroma1 it becomes buff2 when reduced in ,,luminosity1 a cool brown4 ,see ,brown4 ,,veronese ,,green4--,a pigment consisting of hydrated chromium sesquioxide4 ,it is a clear bluish green of great permanency4 ,also called ,viridian4 ,,index ,,by ,,paragraphs4 ,balance of color1 #bc1 #dg1 #fg1 #ge-gg1 #ha-hf1 #ajf1 #ajh1 #aaa1 #aad1 #acb1 #acf1 #adb1 #adg1 ,appendix ,,iii4 ,black1 #ab1 #af1 #bb1 #ca1 #da1 #ed1 #ee1 #fe1 #ia1 #aai4 ,blue1 #i1 #ab1 #af1 #cd1 #ajd1 #adf1 #adg4 ,brewster's theory1 ,appendix ,,iii4 ,charts of the color sphere1 #ad1 #ag1 #abf1 #abg1 #ace1 #acf1 #adj4 ,chevreul1 ,appendix ,,iii41 ,v4 ,chroma1 #c1 #d1 #h1 #aa1 #ad1 #ba-bd1 #bh1 #ci1 #dj1 #db1 #de1 #fd1 #gf1 #gh1 #hb1 #hh1 #id1 #ie1 #aje1 #aba1 #acb4 ,scale of1 #ab1 #ai1 #be1 #ca-ce1 #db1 #acc4 ,strongest1 #cb1 #cd1 #db4 ,chromatic tuning fork1 #aag1 #aah1 #aai-abg4 ,circuit1 inclined1 #af1 #ag1 #ig4 ,color1 apparatus1 #c1 #h1 #ad1 #acb4 ,atlas1 #abi4 ,balance1 #bc1 #dg1 #fg1 #ge-gg1 #ha-hf 7triple71 #ajf1 #ajh1 #aaa1 #aad1 #acb1 #acf1 #adb1 #adg4 ,blindness1 #ahb1 #ahc4 ,charts1 #ad1 #ag1 #abf1 #abg1 #ace1 #acf1 #adj4 ,circuit1 #ed1 #eh1 #ei4 ,complementary1 #gf1 #gg4 ,color1 dimensions of1 #c1 #h1 #i1 #ac1 #be1 #ec1 #id1 #aaf4 ,curves1 #id4 ,discs1 ,maxwell's1 #gf1 #ic1 #ajf-aab1 #aac1 #aag4 ,harmony1 #dg1 #gg1 #hf1 #ade-adh1 #aea-agd1 #ahj4 ,hand as a holder of1 #ed-eh4 ,key of1 #f1 #aea1 #aeb4 ,language1 poverty of1 #e1 #age4 ,lists1 #aca4 ,measured1 #c1 #ad1 #cb4 ,meridians1 #acf1 #acg4 ,middle1 #bh1 #bi1 #dj-db1 #aac4 ,misnomers1 ,appendix ,i4 ,mixture1 #ef-gb4 ,names1 #a1 #b1 #ad1 #ai1 #be1 #ij1 #ia1 #aca4 ,notation1 #cf1 #cg1 #dj-db1 #dg1 #fg1 #gb1 #hf1 #aja1 #acc4 ,orange1 #i-aa1 #hi1 #abc4 ,parallels1 #ab1 #aai4 ,paths1 #aeg1 #aeh1 #afj-afd4 ,perception1 #bg1 #bi1 #ci1 #agi4 ,principal 7#e71 #d1 #af1 #ba1 #bf1 #ca1 #cd1 #dj1 #ed1 #ef1 #eg4 ,principal 7#e7 and intermediates 7#e71 #ca1 #fj1 #fh1 #aab1 #acd4 ,purity1 #h1 #ai1 #bc1 #hi1 #ih1 #ii4 ,records #ade4 ,relations1 #ad1 #bd1 #cf1 #cg1 #aec4 ,rhythm1 #aff4 ,scale1 #c1 #g1 #bd1 #cj1 #ee1 #abj1 #adj1 ,appendix ,,ii4 ,score1 #acc-aci1 #adb1 #agc4 ,sensations1 #c1 #d1 #ae1 #ai1 #ba1 #hg4 ,sequences1 #dg1 #gh1 #gi1 #abj1 #aef1 #afi-aga1 #aha4 ,sir ,isaac ,newton's1 #hi4 ,schemes1 ,appendix ,v4 ,solid1 #ad1 #ai1 #ajb1 #abf1 #abi1 #adj1 #aec4 ,spectral1 #af1 #hh1 #id1 #abi4 ,sphere1 #ab-ag1 #bd1 #be1 #ca1 #dc1 #ee1 #gb1 #ia1 #aja1 #ajb1 #aaa1 #abb1 #acb4 ,standard1 #d1 #bf1 #ce4 ,system1 #c1 #h1 #bh1 #abc1 #acj4 ,need of1 #df1 #adh4 ,tree1 #ad1 #cj-cd1 #dc1 #id1 #ie1 #abd4 ,waves1 #ba1 #bc1 #acf4 ,tones1 #acd4 ,children's color studies1 ,appendix ,,iv4 ,colorist1 #hd1 #aba1 #agg4 ,coloristic art1 #g1 #ch1 #de1 #agg4 ,combined scales1 #ab1 #ad1 #cf1 #cg1 #dg4 ,complements1 #gf1 #gg4 ,course of color study1 #dh-ej4 ,daylight photometer1 #bb1 #ajc1 #aai4 ,enamels1 #bh1 #bi1 #aja1 #aag4 ,fading1 #h1 #bc4 ,false color balance1 ,appendix ,,iii4 ,flat diagrams1 #ad4 ,fundamental sensations1 #bh1 ,appendix ,,iii4 ,green1 #b1 #cb1 #ajd1 #acf1 #acg1 #adj1 #adg1 #adh4 ,hue1 #c1 #d1 #h1 #i-aa1 #ad1 #ah1 #ba-bf1 #cd1 #ci1 #dj1 #dc1 #ed1 #ei1 #gf1 #hb1 #hi1 #aje4 ,scale of1 #ab1 #ai1 #be1 #ca1 #ce1 #abj1 #acc4 ,ideal color system1 #ajj4 ,lambert's pyramid1 note to #ca4 ,luminist1 #aba4 ,masks1 #dg1 #afg-aga4 ,maxwell discs1 #ic1 #ajg1 #aac1 #aag4 ,measurement of colors1 #c1 #h1 #ad1 #aaf1 ,appendix ,,iv4 ,middle gray1 #fa1 #fe1 #gb4 ,middle hues1 #aj1 #bh1 #fe4 ,mixture of hues1 #ef-gb4 ,musical terms used for colors1 #f1 #df1 #adh-aej4 ,neutral axis1 #ca1 #cd1 #fa1 #fe1 #aba4 ,neutral gray1 #aa1 #bc1 #be1 #fb1 #fd1 #fe1 #gb1 #aad1 #ajb4 ,notation diagram1 #adj4 ,orange1 #i-aa1 #ah1 #abc4 ,personal bias1 #add1 #agd4 ,pigments1 #ad1 #bg-bi1 #aja-ajd1 #abe1 #abi4 ,photometer1 #fe4 ,primary sensations1 #hi4 ,prismatic color sphere1 #ih4 ,purple1 #e4 ,rainbow1 #ae1 #ag4 ,red1 middle1 #a1 #cb1 #da1 #fj1 #ff1 #gb1 #ajd1 #aaj1 #abb1 #adg1 #adh4 ,retina1 #ba4 ,rood1 modern chromatics1 ,appendix ,i4 ,runge1 note to #ca1 ,appendix ,v4 ,shades and tints1 #bb4 ,spectrum1 solar1 #ae-ah1 #bg1 #bh1 #hg1 #hh1 #ib1 #ie1 #if4 ,tone1 #f4 ,value1 #c1 #h-aa1 #ad1 #ba-bd1 #bh1 #cd1 #ci1 #dj-dc1 #ed1 #gf1 #gh1 #hb1 #id1 #aje1 #abj1 #acb4 ,scale of1 #ab1 #ai1 #be1 #ca1 #cd1 #ce1 #fd1 #ajb1 #abj1 #acc4 ,vermilion1 #db1 ,appendix ,,iii4 ,vertical 7neutral7 axis1 #ab1 #be1 #ca1 #cd1 #fe1 #fh4 ,violet1 #ij4 ,warm and cold colors1 #gb1 #abc1 note to #acf1 #acg1 #ach4 ,wave lengths1 #ba1 #bb1 #bc1 #hi4 ,white1 #ab1 #af1 #ag1 #bb1 #ca1 #da1 #ed1 #ee1 #fe1 #hg1 #ia1 #ib1 #ii1 #aai4 ,yellow1 #a1 #cb1 #ed1 #ajd1 #acf4 ,the ,,munsell ,,photometer ,patented ,november #ai1 #aija ,a portable1 daylight instrument1 adapted to laboratory work in general1 and of especial service in the comparison of color values4 ,placed in the course of ,optical ,measurements at the ,massachusetts ,institute of ,technology ,price1 #ej ,decoration ,,in ,,preparation ,a ,,color ,,atlas ,also text-books and models specially designed to serve in the education of the color sense