Elementary Color

by Milton Bradley

Active Colors.—Those colors neither passive or neutral. Necessarily both the terms "active" and "passive" used in relation to colors must be quite indefinite.

Complementary Colors.—As white light is the sum of all color if we take from white light a given color the remaining color is the complement of the given color. When the eye has been fatigued by looking intently for a few seconds at a red spot on a white wall and is then slightly turned to the wall, a faint tint of a bluish green is seen, and this is called the accidental color of the red, and is supposed to be identical with its complementary color. If with the disks we determine a color which with a given color will produce by rotation a neutral gray, we have the complementary color more accurately than by any other means at present known in the use of pigmentary colors.

Harmony.—Two colors are said to be in harmony or to combine harmoniously if the effect is pleasing when they are in juxtaposition or are used in a composition.

Spectrum Circuit.—If a pigmentary imitation of the solar spectrum with the addition of violet red at the red end and red violet at the violet end be made, and the two ends joined, we shall have a spectrum circuit. This may be in the form of a circle, an ellipse or an oval.

Primary Colors.—In the Brewster theory red, yellow and blue. In the Young-Helmholtz theory red, green and violet are termed primary colors because it is supposed that from these three sensations all color perceptions are experienced. In purely scientific investigations of color perceptions these last three or others which are supposed to serve the same purpose are also called fundamental colors. Practically every spectrum color is a primary, because each has its own wave length.

Secondary Colors.—In the Brewster theory orange, green and purple have been called secondary because it is claimed that they are produced by the combination of primary colors in pairs.

Tertiary Colors.—A term used in the Brewster theory to denote three classes of colors called russet, citrine and olive, made by mixing the secondaries in pairs. These are all broken spectrum colors. The orange and purple produce russet; the orange and green form citrine; the green and purple, olive. There seems to be no good reason for perpetuating the indefinite terms secondaries and tertiaries as applied to color.

Values.—This word is very freely used in discussing effects in works of art, both in color and in black and white. At present it seems to be a very difficult term to define, and yet each artist is quite sure that he can "feel" it, although few will attempt to put into words a definition satisfactory even to themselves. When an engraver, who is also an artist, attempts to interpret nature in black and white on the metal plate or wooden block, he endeavors to reproduce the "values" of the various parts of the subject before him. In doing this he, for one thing, attempts to produce a variety of neutral grays which will express to the eye by means of black and white lines the same tones of color effect as are seen in the several parts of the subject under investigation. If this were the whole problem the matter would be easily expressed by the disk nomenclature. For instance, if we are to consider a certain red object which may be represented by the standard red disk, we place a medium sized disk of that color on the spindle, and in front of it, smaller disks of white and black united. By rotation the white and black disks become a neutral gray at the center of the red disk. If this gray is made nearly white all observers will agree that the gray is lighter than the red, and if it is nearly black the opinion will be equally unanimous that it is darker than the red. Consequently there evidently must be a gray somewhere between these two extremes which a large majority of experts may agree to be equal in depth or tone to the red, i.e., neither lighter nor darker. But the artist-engraver will insist that to him the term "value" expresses much more than this and that he must use different lines in the sky or distance from those which he uses in the foreground; and some engravers will also insist that two different colors in the foreground must receive different treatment with the graver in order to express their true values. We know that true values of colors are not expressed in a photograph, as the warm colors are too dark and the blue far too light. If the term "value of a color" is to be used as expressing something more than a neutral gray of such a tone as to seem equal to it, then possibly this latter quality must be expressed by the word tone, and yet this use of that word will seem to enlarge its scope beyond its present limits as it now is used to express the relations between the different localities in one scale of color, while this new use will extend to the comparison of tones in various color scales, including neutral grays.

Luminosity.—The luminosity of a color is determined by comparing it with a neutral gray. When a color seems to be of the same brightness as a given neutral gray, i.e., not lighter nor darker, then that gray is its measure of luminosity.

A noted authority says: "No colored object can have the luminosity of a white object reflecting practically the whole of the light impinging upon it. Therefore if we take absolute reflection as 100 a fraction of 100 will give the relative luminosity of any body." Luminosity is another expression of the quality above described as forming a prominent feature in the term values.