It probably is unnecessary to state that these experiments may be made with any color and its complementary and that red and blue-green are used here merely as an example.
Another phase of the same physical effect is seen under other conditions which may at first seem to be quite different from those described, but which on examination appear somewhat similar.
It is a well established fact that when two surfaces approximating each other in color, as red and orange for example, are placed side by side, both are rendered less brilliant, an effect which might be reasonably expected because in order to see both the eye is naturally directed first to one and then to the other, and in each case the after image induced is a green-blue or blue-green, which being approximately complementary to both, dulls both. Or in other words, it is as though one examines for a long time a line of goods of similar colors so that the eye becomes fatigued and the color dulled. It is said that a good salesman of colored materials will endeavor to occasionally attract a customer's attention for a few moments to some other colors approximating a complementary, so that when the attention is again directed to the goods under consideration the full effect of the color may be secured.
If it is true that the phenomenon of the after image is the cause of the peculiar effects expressed by the terms simultaneous, successive and mixed contrasts, and that by these effects all harmonies in color are governed, it is certainly profitable to understand them while using color material with the children, for their good as well as our own pleasure.
Contrasted Harmony.
Returning to our classification of harmonies, already stated, we find the first to be Contrasted Harmony, which covers those combinations in which a positive color, as a spectrum color for example, is combined with white, black or gray, leaving out for the present silver and gold, which may be confusing, and can at best be used only as outlines.
The simplest combinations of colors are found in this class, all of which are not equally harmonious, and some may not perhaps be entitled to be classed as harmonies, although not positively inharmonious. In this class, as in all others, there is involved contrast of tone and contrast of color, which may best be considered in several divisions.
Color with White.
According to the results of Chevreul's elaborate experiments the effect of a combination of an active color with white is to render the color more brilliant and to give to the white the effect of the complementary of the active color. He admits that the modification of white is very indefinite, but claims that, knowing what to expect, a complementary effect may be seen which otherwise would not be noticed. There is also a contrast of tone which in all cases tends to strengthen a color when used with white.