A Color Notation Part 5

_S_, DIFFUSING SCREEN, placed over front apertures, to evenly distribute the light.]

(66) When this numbered scale of values is familiar, it serves not only to describe light and dark grays, but the value of colors which are at the same level in the scale. Thus R7 (popularly called a tint of red) is neither lighter nor darker than the gray of N7. A numeral written above to the right always indicates _value_, whether of a gray or a color, so that R1, R2, R3, R4, R5, R6, R7, R8, R9, describes a regular scale of red values from black to white, while G1, G2, G3, etc., is a scale of green values.

(67) This matter of a notation for colors will be more fully worked out in Chapter VI., but the letters and numerals already described greatly simplify what we are about to consider in the mixture and balance of colors.

+Mixture of light hues with dark hues.+

(68) Now that we are supplied with a decimal scale of grays, represented by divisions of the neutral axis (N1, N2, etc.), and a corresponding decimal scale of value for each of the ten hues ranged about the equator (R1, R2,-- YR1, YR2,-- Y1, Y2,-- GY1, GY2,-- and so on), traced by ten equidistant meridians from black to white, it is not difficult to foresee what the mixture of any two colors will produce, whether they are of the same level of value, as in the colors of the equator already considered, or whether they are of different levels.

[Ill.u.s.tration: Fig. 10.]

(69) For instance, let us mix a light yellow (Y7) with a dark red (R3).

They are neighbors in hue, but well removed in value. A line joining them centres at YR5. This describes the result of their mixture,--a value intermediate between 7 and 3, with a hue intermediate between R and Y. It is a yellow-red of middle value, popularly called "dark orange." But, while this term "dark orange" rarely means the same color to three different people, these measured scales give to YR5 an unmistakable meaning, just as the musical scale gives an unmistakable significance to the notes of its score.

(70) Evidently, 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 use.

(71) If Y9 and R5 be chosen for mixture, we know at once that they unite in YR7, which is two steps of the value scale above the middle; while Y6 and R2 make YR4, which is one step below the middle. Charts prepared with this system show each of these colors and their mixture with exactness.

(72) The foregoing mixtures of dark reds and light yellows are typical of the union of light and dark values of any neighboring hues, such as yellow and green, green and blue, blue and purple, or purple and red.

Next let us think of the result of mixing different values in opposite hues; as, for instance, YR7 and B3 (Fig. 11). To this combination the color sphere gives a ready answer; for the middle of a straight line through the sphere, and joining them, coincides with the neutral centre, showing that they _balance in neutral gray_. This is also true of any opposite pair of surface hues where the values are equally removed from the equator.

[Ill.u.s.tration: Fig. 11.]

(73) Suppose we subst.i.tute familiar flowers for the notation, then YR7 becomes the b.u.t.tercup, and B3 is the wild violet. But, in comparing the two, the eye is more stimulated by the b.u.t.tercup than by the violet, not alone because it is lighter, but because it is stronger in chroma; that is, farther away from the neutral axis of the sphere, and in fact out beyond its surface, as shown in Fig. 11.

The head of a pin stuck in toward the axis on the 7th level of YR may represent the 9th step in the scale of chroma, such as the b.u.t.tercup, while the "modest" violet with a chroma of only 4, is shown by its position to be nearer the neutral axis than the brilliant b.u.t.tercup by five steps of chroma. This is the third dimension of color, and must be included in our notation. So we write the b.u.t.tercup YR 7/9 and the violet B 3/4,--chroma always being written below to the right of hue, and value always above. (This is the invariable order: HUE {VALUE/CHROMA}.)

(74) A line joining the head of the pin mentioned above with B 3/4 does not pa.s.s through the centre of the sphere, and its middle point is nearer the b.u.t.tercup than the neutral axis, showing that the hues of the b.u.t.tercup and violet _do not balance in gray_.

+The neutral centre is a balancing point for colors.+

(75) This raises the question, What is balance of color? Artists criticise the color schemes of paintings as being "too light or too dark" (unbalanced in value), "too weak or too strong" (unbalanced in chroma), and "too hot or too cold" (unbalanced in hue), showing that this is a fundamental idea underlying all color arrangements.

(76) Let us a.s.sume that the centre of the sphere is the natural balancing point for all colors (which will be best shown by Maxwell discs in Chapter V., paragraphs 106-112), then color points equally removed from the centre must balance one another. Thus white balances black. Lighter red balances darker blue-green. Middle red balances middle blue-green. In short, every straight line through this centre indicates opposite qualities that balance one another. The color points so found are said to be "_complementary_," for each supplies what is needed to complement or balance the other in hue, value, and chroma.

(77) The true complement of the b.u.t.tercup, then, is not the violet, which is too weak in chroma to balance its strong opposite. We have no blue flower that can equal the chroma of the b.u.t.tercup. Some other means must be found to produce a balance. One way is to use more of the weaker color. Thus we can make a bunch of b.u.t.tercups and violets, using twice as many of the latter, so that the eye sees an _area_ of blue twice as great as the _area_ of yellow-red. Area as a compensation for inequalities of hue, value, and chroma will be further described under the harmony of color in Chapter VII.

(78) But, before leaving this ill.u.s.tration of the b.u.t.tercup and violet, it is well to consider another color path connecting them which does not pa.s.s through the sphere, _but around it_ (Fig. 12). Such a path swinging around from yellow-red to blue slants downward in value, and pa.s.ses through yellow, green-yellow, green, and blue-green, tracing a _sequence of hue_, of which each step is less chromatic than its predecessor.

[Ill.u.s.tration: Fig. 12.]

This diminis.h.i.+ng sequence is easily written thus,--YR 8/9, Y 7/8, GY 6/7, G 5/6, BG 4/5, B 3/4,--and is shown graphically in Fig. 12. Its hue sequence is described by the initials YR, Y, GY, G, BG, and B. Its value-sequence appears in the upper numerals, 8, 7, 6, 5, 4, and 3, while the chroma-sequence is included in the lower numerals, 9, 8, 7, 6, 5, and 4. This gives a complete statement of the sequence, defining its peculiarity, that at each change of hue there is a regular decrease of value and chroma. Nature seems to be partial to this sequence, constantly reiterating it in yellow flowers with their darker green leaves and underlying shadows. In spring time she may contract its range, making the blue more green and the yellow less red, but in autumn she seems to widen the range, presenting strong contrasts of yellow-red and purple-blue.

(79) Every day she plays upon the values of this sequence, from the strong contrasts of light and shadow at noon to the hardly perceptible differences at twilight. The chroma of this sequence expands during the summer to strong colors, and contracts in winter to grays. Indeed, Nature, who would seem to be the source of our notions of color harmony, rarely repeats herself, yet is endlessly balancing inequalities of hue, value, and chroma by compensations of quant.i.ty.

(80) So subtle is this equilibrium that it is taken for granted and forgotten, except when some violent disturbance disarranges it, such as an earthquake or a thunder-storm.

+The triple nature of color balance ill.u.s.trated.+

(81) The simplest idea of balance is the equilibrium of two halves of a stick supported at its middle point. If one end is heavier than the other, the support must be moved nearer to that end.

But, since color unites three qualities, we must seek some type of _triple balance_. The game of jackstraws ill.u.s.trates this, when the disturbance of one piece involves the displacement of two others. 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 examples.

[Ill.u.s.tration: Fig. 14.]

(82) Triple balance may be graphically shown by three discs in contact.

Two of them are suspended by their centres, while they remain in touch with a third supported on a pivot, as in Fig. 14. Let us call the lowest disc Hue (H), and the lateral discs Value (V) and Chroma (C). Any dip or rotation of the lower disc H will induce sympathetic action in the two lateral discs V and C. When H is inclined, both V and C change their relations to it. If H is raised vertically, both V and C dip outward. If H is rotated, both V and C rotate, but in opposite directions. Indeed, any disturbance of V affects H and C, while H and V respond to any movement of C. So we must be prepared to realize that any change of one color quality involves readjustment of the other two.

(83) Color balance soon leads to a study of optics in one direction, to aesthetics in another, and to mathematical proportions in a third, and any attempt at an easy solution of its problems is not likely to succeed. It is a very complicated question, whose closest counterpart is to be sought in musical rhythms. The fall of musical impulses upon the ear can make us gay or sad, and there are color groups which, acting through the eye, can convey pleasure or pain to the mind.

(84) A colorist is keenly alive to these feelings of satisfaction or annoyance, and consciously or unconsciously he rejects certain combinations of color and accepts others. Successful pictures and decorative schemes are due to some sort of balance uniting "light and shade" (value), "warmth and coolness" (hue), with "brilliancy and grayness" (chroma); for, when they fail to please, the mind at once begins to search for the unbalanced quality, and complains that the color is "too hot," "too dark," or "too crude." This effort to establish pleasing proportions may be unconscious in one temperament, while it becomes a matter of definite a.n.a.lysis in another. Emerson claimed that the unconscious only is complete. We gladly permit those whose color instinct is unerring--(and how few they are!)--to neglect all rules and set formulas. But education is concerned with the many who have not this gift.

(85) Any real progress in color education must come not from a blind imitation of past successes, but by a study into the laws which they exemplify. To exactly copy fine j.a.panese prints or Persian rugs or Renaissance tapestries, while it cultivates an appreciation of their refinements, does not give one the power to create things equally beautiful. The masterpieces of music correctly rendered do not of necessity make a composer. The musician, besides the study of masterpieces, absorbs the science of counterpoint, and records by an unmistakable notation the exact character of any new combination of musical intervals which he conceives.

(86) So must the art of the colorist be furnished with a scientific basis and a clear form of color notation. This will record the successes and failures of the past, and aid in a search, by contrast and a.n.a.lysis, for the fundamentals of color balance. Without a measured and systematic notation, attempts to describe color harmony only produce hazy generalities of little value in describing our sensations, and fail to express the essential differences between "good" and "bad" color.

APPENDIX TO CHAPTER III.

[Ill.u.s.tration]

FALSE COLOR BALANCE. There is a widely accepted error that red, yellow, and blue are "primary," although Brewster's theory was long ago dropped when the elements of color vision proved to be RED, GREEN, and VIOLET-BLUE. The late Professor Rood called attention to this in Chapters VIII.-XI. of his book, "Modern Chromatics," which appeared in 1879. Yet we find it very generally taught in school. Nor does the harm end there, for placing red, yellow, and blue equidistant in a circle, with orange, green, and purple as intermediates, the teacher goes on to state that opposite hues are complementary.

Red is thus made the complement of Green, Yellow Purple, and Blue Orange.

Unfortunately, each of these statements is wrong, and, if tested by the mixture of colored lights or with Maxwell's rotating discs, their falsity is evident.

There can be no doubt that green is not the complement of red, nor purple of yellow, nor orange of blue, for neither one of these pairs unites as it should in a balanced neutrality, and a total test of the circle gives great excess of orange, showing that red and yellow usurp too great a portion of the circ.u.mference. Starting from a false basis, the Brewster theory can only lead to unbalanced and inharmonious effects of color.

The fundamental color sensations are RED, GREEN, and VIOLET-BLUE.

RED has for its true complement BLUE-GREEN, GREEN RED-PURPLE, and VIOLET-BLUE YELLOW,

all of the hues in the right-hand column being compound sensations. The sensation of green is not due to a mixture of yellow and blue, as the absorptive action of pigments might lead one to think: GREEN IS FUNDAMENTAL, and not made by mixing any hues of the spectrum, while YELLOW IS NOT FUNDAMENTAL, but caused by the mingled sensations of red and green. This is easily proved by a controlled spectrum, for all yellow-reds, yellows, and green-yellows can be matched by certain proportions of red and green light, all blue-greens, blues, and purple-blues can be obtained by the union of green and violet light, while purple-blue, purple, and red-purple result from the union of violet and red light. But there is no point where a mixture gives red, green, or violet-blue. They are the true primaries, whose mixtures produce all other hues.

Studio and school-room practice still cling to the discredited theory, claiming that, if it fails to describe our color sensations, yet it may be called practically true of pigments, because a red, yellow, and blue pigment suffice to imitate most natural colors. This discrepancy between pigment mixture and retinal mixture becomes clear as soon as one learns the physical make-up and behavior of paints.

[Ill.u.s.tration: { Vermilion Spectra { { Em. Green P. B. G. Y. R.]

Spectral a.n.a.lysis shows that no pigment is a pure example of the dominant hue which it sends to the eye. Take, for example, the very chromatic pigments representing red and green, such as vermilion and emerald green. If each emitted a single pure hue free from trace of any other hue, then their mixture would appear yellow, as when spectral red and green unite. But, instead of yellow, their mixture produces a warm gray, called brown or "dull salmon," and this is to be inferred from their spectra, where it is seen that vermilion emits some green and purple as well as its dominant color, while the green also sends some blue and red light to the eye.[20]

[Footnote 20: See Rood, Chapter VII., on Color by Absorption.]