Page:A color notation (Munsell).djvu/120

 —Objectively, that quality of a thing or appearance which is perceived by the eye alone, independently of the form of the thing; subjectively, a sensation peculiar to the organ of vision, and arising from the optic nerve.

—Incapacity for perceiving colors, independent of the capacity for distinguishing light and shade. The most common form is inability to perceive red as a distinct color, red objects being confounded with gray or green; and next in frequency is the inability to perceive green.

—The numbers which measure the quantities, as well as any other system of three numbers for defining colors, are called constants of color.

—Colors vary in CHROMA, or freedom from ad-mixture of white light; in BRIGHTNESS, or luminosity; and in HUE, which roughly corresponds to the mean wave length of the light emitted.

—Those pairs of color which when mixed produce white or gray light, such as red and green-blue, yellow and indigo-blue, green-yellow and violet.

—The red, green, and violet light of the spectrum, from the mixture of which all other colors can be produced. Also called fundamental colors.

—In commerce, any dyewood, lichen, or dyecake used in dyeing and staining.

—Light produced by electricity and of two general kinds, the arc. light and the incandescent light. In the first the voltaic arc is employed. In the second a resisting conductor is rendered incandescent by the current.

—In the fine arts a vitreous substance or glass, opaque or transparent, and variously colored, applied as a coating on a surface of metal or of porcelain.