Page:Color standards and color nomenclature (Ridgway, 1912).djvu/36

 Chroma.—Degree of freedom from white light; purity, intensity or fullness of color.

Luminosity.—Degree of brightness or clearness. The relative luminosity of the spectrum colors is as follows: [Yellow (brightest)?], orange yellow; orange; greenish-yellow, yellow-green, and green; orange-red; red and blue (equal); violet-blue, blue-violet, violet.

Warm Colors.—The colors nearer the red end of the spectrum or those of longer wave-lengths (red, orange, and yellow, and connecting hues) "and combinations in which they predominate."

Cool, or Cold, Colors.—The colors nearer the violet end of the spectrum or those of shorter wave-length, especially blue and green-blue. "But it is, perhaps, questionable whether green and violet may be termed either warm or cool."

Complementary Color.—"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 any two colors or hues which when combined in proper proportion on the color-wheel produce, by rotation, neutral gray, these two colors each represent the complementary of the other.

Constants of Color.—The constants of color are numbers which measure (1) the wave-length, (2) the chroma, and (3) the luminosity.

In addition to the terms defined above there are many others, for which the reader is referred to the chapter on "Color Definitions" on pages 23-30 of Milton Bradley's excellent and most useful book "Elementary Color."