changes in hue and saturation which they would have suffered by contrast with red. Thus orange will stand nearer the center and somewhat nearer yellow, whereas green-blue will merely be removed farther from the center, which means that orange will become less saturated and yellower, whereas green-blue will increase in saturation but be unaltered in hue.
In general we may say that the effect produced by contrasting two colors is to move them farther apart on the chromatic circle, thus causing mainly a change in hue in the case of colors that stand near one another, but making a change in saturation in those which are far apart.
In order that the contrast effects may be taken full advantage of, certain conditions must be fulfilled. The most important of these are as follows: (1) The complementary tint which gray assumes is most vivid when it is somewhat darker (i. e., of less brightness, see p. 460) than the hue against which it is apposed, in the case of the warm colors (the reds, oranges and yellows), and when it is lighter in the case of the cold colors (the greens and blues). The dividing line between the warm and cold colors may be taken as that joining the complementaries, 5'ellow-green and violet. (2) When a color of low saturation (i. e., nearly a gray) is apposed to one of high saturation and of complementary hue, the former will become more saturated, and conversely, if two colors which are identical in hue but of unequal saturation be apposed, the paler one may appear gray. When they are not complementary, the hue which undergoes the greater change is that which is the paler. (3) The greatest effects are produced when the color field, whose hue it is desired to alter, is much smaller in extent than that of its complementary and when it is completely surrounded by the latter. By placing a thick black line between the areas the complementary effects may be suppressed. Thus, the complementary hue which a piece of gray paper placed on a colored field assumes when it is viewed through tissue paper becomes much less evident if a thick black line be drawn on the tissue paper at the edge of the gray. When the color areas are large it is at the edge only that the complementary influence is noticeable. On the other hand when a colored area is very small it undergoes no complementary change, but merely blends with the neighboring color. (4) To obtain full advantage of color apposition the colored patterns should be very simple and of similar texture and their surfaces should be broken up by detail to the least possible degree. (5) The most marked complementary effects are obtained when the opposing hues are of equal brightness.
When we attempt to employ the chromatic circle for another purpose, namely for determining what will be pleasing and what displeasing color combinations, we find that its use is somewhat limited. This is because a psychological influence enters into our judgment in such cases.
