[(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 R5/9 means
| HUE (red), | VALUE (5) | , | and will be found to represent the qualities of the pigment vermilion.[14] |
| CHROMA (9) |
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 R5/, 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/, R2/, 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 /9, seeing that this describes the chromas of red, but leaves out its values. R5/1, R5/5, R5/9, 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.