The Afterimage

This kind of compensatory response in the eye is always present, but we are not often aware of it. The afterimage of every color in a color scheme or in a painting will affect every other color to some degree, favorably or unfavorably. An achromatic or neutral tone will pick up color from the afterimage, if it is placed within or beside a bright hue. White is capable of becoming quite saturated with the afterimage of a strong stimulus. Even black will appear to shift to warm if placed within or beside a cool color [say, a strong blue-green], or to cool if placed with a warm color [a red-orange]; which is to admit that, if black is minus color on its own, it can borrow color from the afterimage of a strong neighbor. Painters have been aware of these and similar phenomena for a long time. The effect of the afterimage is more noticeable in small areas and along the edges of adjacent colors, suggesting a good reason why we should use black outlining knowingly or with caution, or not at all, where subtle color interactions are wanted. Black outlining may be used in other circumstances to reinforce or deepen large areas of rather strong color;

According to Goethe, complementary colors "demand each other." It was Goethe who described how objects lit by a colored light cast shadows that are suffused with the complementary of that light [notice, for instance, how yellowish late-afternoon sunlight casts blue shadows of limbs and branches upon a white wall]. [17] He felt, perhaps rightly, that one of the true secrets of using color lies in this "calling up" of a color by its opposite. Chevreul described how any two colors, when placed side by side, will appear to modify each other in both hue [color identity] and value [lightness/darkness], how the afterimage of each will overlay the other--hence the meaning of his term simultaneous contrast, or mutual contrast. Only in the case of true complementaries will colors intensify each other without otherwise altering each other as to hue, according to his judgment. When dealing with colors in juxtaposition, we are dealing unavoidably with optical and even emotional trickery.

Our color wheel [essentially Rood's wheel] places yellow at the top and violet at the bottom. Stepping downward from yellow on the warm side are orange-yellow [that is, orangish yellow], orange, orange-red [orangish red or vermilion], crimson [or purple-red], purple, and violet. Stepwise down the cool side of the wheel from yellow are green-yellow [or greenish yellow], green, blue-green [bluish green], green-blue [greenish blue], blue, and ultramarine blue. Each and every color is in its natural order, is in prime condition, and as each takes its proper place down one side of the wheel or the other from yellow, it should appear to be slightly darker in value than the one above it. This must be understood if this wheel is to serve the purposes for which it is in tended--chiefly for noting what happens to colors when they are inverted upward or downward from their natural positions. [pp. 93-94]