The use of color in decorative composition will be discussed in several of the later chapters. The student of interior decoration must, however, be alert to gather ideas helpful in color practice from every practicable source - from nature, from art, and from books. There is a considerable literature of color, and much may be learned from reading; but this reading must be done intelligently. We have seen that the study of color is made difficult by the lack of a definite system of color notation, and by the fact that one class of writers employs the theory and terminology of colored light, and another class the theory and terminology of pigments. A third source of confusion exists in the fact that most of what has been written of color practice applies primarily to the art of painting, and very little of it directly to the art of interior decoration.

In their use of color painting and decoration differ widely, as Professor Raymond has pointed out, both in motive and technique; and what is said about one art is accordingly only partially applicable to the other. The painter uses color in order to represent nature, while the decorator uses it for its own sake. (The most modern of the painters, who have wholly discarded representation, in effect use color as it is used in decoration.) The painter deals with small areas, which he covers with small masses of color revealing wide variation in hue and practically unlimited variation in tone. The decorator deals with large areas, covered with large masses of color, and revealing relatively few hues and a relatively limited variation in tone. One art uses chiefly the greens, grays, purples and light blues so common in nature, while the other uses chiefly the warm colors, and blue in darker rather than in lighter tones. The painter is frequently justified, in order faithfully to set forth what he sees, in introducing inharmonious colors; the decorator, who uses color for its esthetic value purely, has no such justification. Finally, the primary aim in painting is to create something which shall be beautiful in itself; while the primary aim in interior decoration is to create something which shall be beautiful in conjunction with, and as a background for, the people who use the room. Merely to state these differences is enough to emphasize the need for caution in applying to the art of interior decoration the general literature of color.