# A Color Notation/Chapter 2

(20) The three color qualities are hue, value, and chroma.
HUE is the name of a color.
(21) Hue is the quality by which we distinguish one color from another, as a red from a yellow, a green, a blue, or a purple. This names the hue, but does not tell whether it is light or dark, weak or strong,—leaving us in doubt as to its value and its chroma.
Science attributes this quality to difference in the LENGTH of ether waves impinging on the retina, which causes the sensation of color. The wave length M. 5269 gives a sensation of green, while M. 6867 gives a sensation of red.
VALUE is the light of a color.
(22) Value is the quality by which we distinguish a light color from a dark one. Color values are loosely called tints and shades, but the terms are frequently misapplied. A tint should be a light value, and a shade should be darker; but the word “shade” has become a general term for any sort of color, so that a shade of yellow may prove to be lighter than a tint of blue. A photometricscale of value places all colors in relation to the extremes of white and black, but cannot describe their hue or their chroma.
​Science describes this quality as due to difference in the height or amplitude of ether waves impinging on the retina. Small amplitudes of the wave lengths given in paragraph 21 produce the sensation of dark green and dark red: larger amplitudes give the sensation of lighter green and lighter red.
CHROMA is the strength of a color.
(23) Chroma is the quality by which we distinguish a strong color from a weak one. To say that a rug is strong in color gives no hint of its hues or values, only its chromas. Loss of chroma is loosely called fading, but this word is frequently used to include changes of value and hue. Take two autumn leaves, identical in color, and expose one to the weather, while the other is waxed and pressed in a book. Soon the exposed leaf fades into a neutral gray, while the protected one preserves its strong chroma almost intact. If, in fading, the leaf does not change its hue or its value, there is only a loss of chroma, but the fading process is more likely to induce some change of the other two qualities. Fading, however, cannot define these changes.
Science describes chroma as the purity of one wave length separated from all others. Other wave lengths intermingling, make its chroma less pure. A beam of daylight can combine all wave lengths in such balance as to give the sensation of whiteness, because no single wave is in excess.
(24) The color sphere (see Fig. 1) is a convenient model to illustrate these three qualities,—hue, value, and chroma,—and unite them by measured scales.
(25) The north pole of the color sphere is white, and the south pole black. Value or luminosity of colors ranges between these two extremes. This is the vertical scale, to be memorized as V, ​the initial for both value and vertical. Vertical movement through color may thus be thought of as a change of value, but
not as a change of hue or of chroma. Hues of color are spread around the equator of the sphere. This is a horizontal scale, memorized as H, the initial for both hue and horizontal. Horizontal movement around the color solid is thus thought of as a change of hue, but not of value or of chroma. A line inward from the strong surface hues to the neutral gray axis, traces the graying of each color, which is loss of chroma, and conversely a line beginning with neutral gray at the vertical axis, and becoming more and more colored until it passes outside the sphere, is a scale of chroma, which is memorized as C, the initial both for chroma and centre. Thus the sphere lends its three dimensions to color description, and a color applied anywhere within, without, or on its surface is located and named by its degree of hue, of value, and of chroma.
HUES first appeal to the child, VALUES next, and CHROMAS last.
(26) Color education begins with ability to recognize and name certain hues, such as red, yellow, green, blue, and purple (see paragraphs 182 and 183). Nature presents these hues in union with such varieties of value and chroma that, unless there be some standard of comparison, it is impossible for one person to describe them intelligently to another.
(27) The solar spectrum forms a basis for scientific color analysis, taught in technical schools; but it is quite beyond the comprehension of a child. He needs something more tangible and constantly in view to train his color notions. He needs to handle colors, place them side by side for comparison, imitate them with ​crayons, paints, and colored stuffs, so as to test the growth of perception, and learn by simple yet accurate terms to describe each by its hue, its value, and its chroma.
(28) Pigments, rather than the solar spectrum, are the practical agents of color work. Certain of them, selected and measured by this system (see Chapter V.), will be known as middle colors, because they stand midway in the scales of value and chroma. These middle colors are preserved in imperishable enamels, so that the child may handle and fix them in his memory, and thus gain a permanent basis for comparing all degrees of color. He learns to grade each middle color to its extremes of value and chroma.
(29) Experiments with crayons and paints, and efforts to match middle colors, train his color sense to finer perceptions. Having learned to name colors, he compares them with the enamels of middle value, and can describe how light or dark they are. Later he perceives their differences of strength, and, comparing them with the enamels of middle chroma, can describe how weak or strong they are. Thus the full significance of these middle colors as a practical basis for all color estimates becomes apparent; and, when at a more advanced stage he studies the best examples of decorative color, he will again encounter them in the most beautiful products of Oriental art.
Is it possible to define the endless varieties of color?
(30) At first glance it would seem almost hopeless to attempt the naming of every kind and degree of color. But, if all these varieties possess the same three qualities, only in different degrees, and if each quality can be measured by a scale, then there is a clue to this labyrinth.
A COLOR SPHERE and COLOR TREE to unite hue, value, and chroma.
(31) This clue is found in the union of these three qualities by measured scales in a color sphere and color tree. The equator
of the sphere may be divided into ten parts, and serve as the scale of hue, marked R, YR, Y, GY, G,.BG, B, PB, P; and RP. Its vertical axis may be divided into ten parts to serve as the scale of value, numbered from black (0) to white (10). Any perpendicular to the neutral axis is a scale of chroma. On the plane of the equator this scale is numbered 1, 2, 3, 4, 5, from the centre to the surface.
(32) This chroma scale may be raised or lowered to any level of value, always remaining perpendicular to the axis, and serving to measure the chroma of every hue at every level of value. The fact that some colors exceed others to such an extent as to carry them out beyond the sphere is proved by measuring instru​ments, but the fact is a new one to many persons, since the training of the color sense has been left so much to guess-work and personal whim that the thought of testing these vagaries is resented as inartistic, mechanical, and even unwise, and the suggestion of written color seems preposterous. Only a few centuries have passed since Pope Gregory's friend said, “Unless musical sounds be retained in the memory, they perish, for they cannot be written”; yet musical intervals are now accurately measured and written, and the time may not be far distant when the sensations of value and chroma will be defined and recorded with equal ease. The chroma of the spectrum is nearly equal through-out, but it is a great mistake to assume the same of pigments. In fact, the best blue-green is but half the chroma of vermilion red; and this becomes evident the moment they are tested by proper instruments. To portray this unbalance, the strongest hues must project unevenly beyond a spherical surface, as shown in the appendix to this chapter.
(33) For this reason the color tree is a completer model than the sphere, although the simplicity of the latter makes it best for a child’s comprehension.
(34) The color tree is made by taking the vertical axis of the sphere, which carries a scale of value, for the trunk. The branches are at right angles to the trunk; and, as in the sphere, they carry the scale of chroma. Colored balls on the branches tell their Hue. In order to show the maxima of color, each branch is attached to the trunk (or neutral axis) at a level demanded by its value,—the yellow nearest white at the top, then the green, red, blue, and purple branches, approaching black in the order of their lower values. It will be remembered that the chroma of the sphere ceased with 5 at the equator. The color tree pro​longs this through 6, 7, 8, and 9. The branch ends carry colored balls, representing the most powerful red, yellow, green, blue, and purple pigments which we now possess, and could be lengthened, should stronger chromas be discovered.
(35) Such models set up a permanent image of color relations. Every point is self-described by its place in the united scales of hue, value, and chroma. These scales fix each new perception of color in the child’s mind by its situation in the color solid. The importance of such a definite image can hardly be overestimated, for without it one color sensation tends to efface another. When the child looks at a color, and has no basis of comparison, it soon leaves a vague memory that cannot be described. These models, on the contrary, lead to an intelligent estimate of each color in terms of its hue, its value, and its chroma; while the permanent enamels correct any personal bias by a definite standard.
(36) Thus defined, a color falls into logical relation with all other colors in the system, and is easily memorized, so that its image may be recalled at any distance of time or place by the notation:
(37) These solid models help to memorize and assemble colors and the memory is further strengthened by a simple notation, which records each color so that it cannot be mistaken for any other. By these written scales a child gains an instinctive estimate of relations, so that, when he is delighted with a new color combination, its proportions are noted and understood.
(38) Musical art has long enjoyed the advantages of a definite scale and notation. Should not the art of coloring gain by similar definition? The musical scale is not left to per​sonal whim, nor does it change from day to day; and something as clear and stable would be an advantage in training the color sense.
(39) Perception of color is crude at first. The child sees only the most obvious distinctions, and prefers the strongest stimulation. But perception soon becomes refined by exercise, and, when a child tries to imitate the subtle colors of nature with paints, he begins to realize that the strongest colors are not the most beautiful,—rather the tempered ones, which may be compared to the moderate sounds in music. To describe these tempered colors, he must estimate their hue, value, and chroma, and be able to describe in what degree his copy departs from the natural color. And, with this gain in perception and imitation of natural color, he finds a strong desire to invent combinations to please his fancy. ‘Thus the study divides into three related attitudes, which may be called recognition, imitation, and invention. Rec- ognition of color is fundamental, but it would be tedious to spend a year or two in formal and dry exercises to train recognition of color alone; for each step in recognition of color is best tested by exercise in its imitation and arrangement. When perception becomes keener, emphasis can be placed on imitation of the colors found in art and in nature, resting finally on the selection and grouping of colors for design.”
Every color can be recognized, named, matched, imitated, and written by its HUE, VALUE, and CHROMA.
(40) The notation used in this system places Hue (expressed by an initial) at the left; Value (expressed by a number) at the right and above a line; and Chroma (also expressed by ​a number) at the right, below the line. Thus R5/10 means hue (red), Value (5)/CHROMA (10) and will be found to represent the qualities of the pigment vermilion.
Hue, value, and chroma unite in every color sensation, but the child cannot grasp them all at once. Hue-difference appeals to him first, and he gains a permanent idea of five principal hues from the enamels of middle colors, learning to name, match, imitate, and finally write them by their initials: R (red), Y (yellow), G (green), B (blue), and P (purple). Intermediates formed by uniting successive pairs are also written by the joined initials, YR (yellow-red), GY (green-yellow), BG (blue-green), PB (purple-blue), and RP (red-purple).
(41) Ten differences of hue are as many as a child can render at the outset, yet in matching and imitating them he becomes aware of their light and dark quality, and learns to separate it from hue as value-difference. Middle colors, as implied by that name, stand midway between white and black,—that is, on the equator of the sphere,—so that a middle red will be written R3/ , suggesting the steps 6, 7, 8, and 9 which are above the equator, while steps 4, 3, 2, and 1 are below. It is well to show only three values of a color at first; for instance, the middle value contrasted with a light and a dark one. These are written R3/ , R5/ , R7/ . Soon he perceives and can imitate finer differences, and the red scale may be written entire, as R1/ , R3/ , R3/ , R4/ , R5/ , R6/ , R7/ , R8/ , R9/ , with black as 0 and white as 10.
(42) Chroma-difference is the third and most subtle color quality. The child is already unconsciously familiar with the middle chroma of red, having had the enamels of middle color always ​in view, and the red enamel is to be contrasted with the strongest and weakest red chromas obtainable. ‘These he writes R /1, R /5, R /10 seeing that this describes the chromas of red, but leaves out its values. R5/1, R5/5, R5/10, is the complete statement, showing that, while both hue and value are unchanged, the chroma passes from grayish red to middle red (enamel first learned) and out to the strongest red in the chroma scale obtained by vermilion.
(43) It may be long before he can imitate the intervening steps of chroma, many children finding it difficult to express more than five steps of the chroma scale, although easily making ten steps of value and from twenty to thirty-five steps of hue. This interesting feature is of psychologic value, and has been followed in the color tree and color sphere.
Does such a scientific scheme leave any outlet for feeling and personal expression of beauty?
(44) Lest this exact attitude in color study should seem inartistic, compared with the free and almost chaotic methods in use, let it be said that the stage thus far outlined is frankly disciplinary. It is somewhat dry and unattractive, just as the early musical training is fatiguing without inventive exercises. The child should be encouraged at each step to exercise his fancy.
(45) Instead of cramping his outlook upon nature, it widens his grasp of color, and stores the memory with finer differences, supplying more material by which to express his sense of coloristic beauty.
(46) Color harmony, as now treated, is a purely personal affair, difficult to refer to any clear principles or definite laws. The very terms by which it seeks expression are borrowed from music, and suggest vague analogies that fail when put to the test. Color ​needs a new set of expressive terms, appropriate to its qualities, before we can make an analysis as to the harmony or discord of our color sensations.
(47) This need is supplied in the present system by measured charts, and a notation. Their very construction preserves the balance of colors, as will be shown in the next chapter, while the chapter on harmony (Chapter VII.) shows how harmonious pairs and triads of color may be found by masks with measured intervals. In fact, 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 harmony. And, although in neither art can training alone make the artist, yet a technical grasp of these formal scales gives acquaintance with the full range of the instrument, and is indispensable to artistic expression. From these color scales each individual is free to choose combinations in accord with his feeling for color harmony.
Let us make an outline of the course of color study traced in the preceding pages.
PERCEPTION of color.
(48)
* Hue-difference.
** Middle hues (5 principals).
** Middle hues (5 intermediates).
** Middle hues (10 placed in sequence as SCALE of HUE).
* Value-difference. ​
** Light, middle, and dark values (without change of hue).
** Light, middle, and dark values (traced with 5 principal hues).
** 10 values traced with each hue. scale of value. The Color Sphere.
* Chroma-difference.
** Strong, middle, and weak chroma (without change of hue).
** Strong, middle and weak chroma (traced with three values without change of hue).
** Strong, middle, and weak chroma (traced with three values and ten hues).
** Maxima of color and their gradation to white, black, and gray. The Color Tree.
EXPRESSION of color.
(49)
* Matching and imitation of hues (using stuffs, crayons, and paints).
* Matching and imitation of values and hues (using stuffs, crayons, and paints).
* Matching and imitation of chromas, values, and hues (using stuffs, crayons, and paints).
* Notation of color. Hue Value/Chroma, H V/C Initial for hue, numeral above for value, numeral below for chroma.
* Sequences of color.
** Two scales united, as hue and value, or chromaand value.
** Three scales united,—each step a change of hue, value, and chroma.
* Balance of color.
** Opposites of equal value and chroma (R 5/5 and BGR 5/5).
** Opposites of equal value and unequal chroma (R3 and BGR 5/3).
** Opposites unequal both in value and chroma (R 7/3 and BG 3/7).
** area as an element of balance.
HARMONY of color.
(50)
* Selection of colors that give pleasure.
** Study of butterfly wings and flowers, recorded by the notation.
** Study of painted ornament, rugs, and mosaics, recorded by the notation.
** Personal choice of color parts, balanced by H, V, C, and area.
** Personal choice of color triads, balanced by H, V, C, and area.
* Grouping of colors to suit some practical use: wall papers, rugs, book covers, etc.
** Their analysis by the written notation.
** Search for principles of harmony, expressed in measured terms.
A definite plan of color study, with freedom as to details of presentation.
(51) Having memorized these broad divisions of the study, a clever teacher will introduce many a detail, to meet the mood of the class, or correlate this subject with other studies, without for a moment losing the thread of thought or befogging the presentation. But to range at random in the immense field of color sensations, without plan or definite aim in view, only courts fatigue of the retina and a chaotic state of mind.
(52) The same broad principles which govern the presentation of other ideas apply with equal force in this study. A little, well apprehended, is better than a mass of undigested facts. If the child is led to discover, or at least to think he is discovering, new things about color, the mind will be kept alert and seek out novel illustrations at every step. Now and then a pupil will be found ​who leads both teacher and class by intuitive appreciation of color, and it is a subtle question how far such a nature can be helped or hurt by formal exercises. But such an exception is rare, and goes to prove that systematic discipline of the color sense is necessary for most children.
(53) Outdoor nature and indoor surroundings offer endless color illustrations. Birds, flowers, minerals, and the objects in daily use take on a new interest when their varied colors are brought into a conscious relation, and clearly named. A tri-dimensional perception, like this sense of color, requires skilful training, and each lesson must be simplified to the last point practicable. It must not be too long, and should lead to some definite result which a child can grasp and express with tolerable accuracy, while its difficulties should be approached by easy stages, so as to avoid failure or discouragement. The success of the present effort is the best incentive to further achievement.
* ↑ See Glossary for definitions of Micron, Photometer, Retina, and Red, also for Hue, Tint, Shade, Value, Color Variables, Luminosity, and Chroma.
* ↑ See Photometer in paragraph 65.
* ↑ See definition of White in Glossary.
* ↑ When recognized for the first time, a middle green, blue, or purple, is accepted by most persons as well within their color habit, but middle red and middle yellow cause somewhat of a shock. “That isn’t red,” they say, “it’s terra cotta.” “Yellow?” “Oh, no, that’s—well, it’s a very peculiar shade.” Yet these are as surely the middle degrees of red and yellow as are the more familiar degrees of green, blue, and purple. This becomes evident as soon as one accepts physical tests of color in place of personal whim. It also opens the mind to a generally ignored fact, that middle reds and yellows, instead of the screaming red and yellow first given a child, are constantly found in examples of rich and beautiful color, such as Persian rugs, Japanese prints, and the masterpieces of painting.
* ↑ See Color Tree in paragraph 14.
* ↑ Unaware that the spherical arrangement had been used years before, I devised a double tetrahedron to classify colors, while a student of painting in 1879. It now appears that the sphere was common property with psychologists, having been described by Runge in 1810. Earlier still, Lambert had suggested a pyramidal form. Both are based on the erroneous assumption that red, yellow, and blue are primary sensations, and also fail to place these hues in a just scale of luminosity. My twirling color solid and its completer development in the present model have always made prominent the artistic feeling for color value. It differs in this and in other ways from previous systems, and is fortunate in possessing new apparatus to measure the degree of hue, value, and chroma.
* ↑ See Course of Study, Part II.
* ↑ See Chapter VI.
* ↑ See Part II., A Color System and Course of Study.
* ↑ See Color Study assigned to each grade, in Part II.
To avoid blundering with pigment colors, it is well to learn their unbalanced value and chroma, as graphically shown on the opposite page. The central drawing of the Color Tree, and half scale sections in the corners, give a measured model of all color relations.
The upper left-hand diagram is a vertical slice through the neutral axis containing the complementary fields of blue and yellow-red (alias orange). This unbalanced pair may be com- pensated by diminishing either the chroma or the area of yellow-red, as explained in paragraph 77 on page 44. The upper right-hand section contains the complementary fields of yellow and purple-blue which are nearly equal in area, but inverted as to luminosity,—a form of balance suggested in paragraph 76. The lower left-hand diagram gives the complementary fields of purple and green-yellow which are nearly compensated, as are the remaining pair of green and red-purple.
The contour of the central drawing shows the most unbalanced fields of red and its complement blue-green, the latter being but half as strong as red. It is this weak blue-green that limits the size of the color sphere, which may be increased as soon as a reliable blue-green of stronger chroma is available. And here let it be added that different makes of pigment vary considerably, while the output of a single maker may vary from year to year, owing to fluctuations in the color bases, which this measured system will detect and rectify.
The importance of understanding these unbalanced qualities of paint can hardly be overstated, and those who find it difficult to ​grasp such relations from a diagram should have a model of the Color Tree at hand when studying these chapters.
Three horizontal slices are taken through the diagrams and central drawing,to represent charts 30, 50, and 70 of the Color Atlas on whose measured scales are printed symbols giving the proportions by which any pair or group of colors may be balanced. This is also illustrated in the folded color plate (V.) at the end of the book. Masks of black paper will aid in the selection of such groups, as suggested in paragraphs 47 and 167-171. In these color scales any fractional part of a decimal series is discarded for the sake of simplicity, but may be estimated by the eye.
The Color Sphere appears in each diagram as a circle struck from middle gray. It excludes the uneven maxima of color described in paragraph 34, and represents Nature’s determination to temper color by dimming the brilliance of white and the blackness of velvet, fading the discords of the bill-board, and enriching the envelope of old paintings, tapestries, ceramics, and prints.
This may be tested in any museum of art, for with the maxima in one hand and the middle colors of the sphere in the other, it becomes evident that the latter abound in the most beautiful examples, while the maxima are absent or admitted only as small accents to balance large fields of quiet chroma.