Contrast of Colors.
If two colors contiguous in the spectrum circuit are placed in juxtaposition the effect of the contrast of hue is to throw them away from each other. For example, if orange red and the red orange papers are put side by side the former will seem more red and the latter more orange. Therefore, when colored papers are pasted up or laid in order to form a spectrum, for example, the colors not only fail to blend together but each line of contact is very disagreeably prominent.
If two colors are separated by a narrow strip of light gray, gold, black or white, the effect is greatly improved. For this reason a design in analogous colors is often improved by separating certain colors by a fine line of black, gold or gray.
If two colors not closely related to each other in the spectrum circuit are placed in juxtaposition, each is modified by an effect which is the complementary of the other. For example, if red and yellow are placed side by side, in contact, the red is rendered more violet by the added effect of blue, which is the complementary of yellow, and the yellow is modified by the blue-green complementary of the red, which tends to dull the yellow and change it slightly toward green.
If blue and yellow are joined both are improved, as the two are so nearly complementary to each other that each is intensified by simultaneous contrast, blue being added to blue and yellow to yellow.