It takes a great deal more experience of color, for instance, to fully appreciate such factors as warm and cool contrasts, complementary contrast, the various types of color interaction. We acquire the habit of examining color studies, old and new, for the tendency of colors to expand and contract, advance and recede. Warm colors often seem nearer and larger than the areas they actually occupy. Yellow spreads more than orange or red. The cool colors tend, in most situations, to appear a bit smaller and more discrete than their ground space.
Grays seem retractive.
Black, however, usually maintains as strong a forward position as white. Yet color and value contrast, hard and soft edges, and other figure-ground factors are operative, often in very unpredictable ways. Geometric shapes or planes may share the same edge, may hinge on one another to create cubic structures or stepwise movements in space. Solid planes may be used with open linear planes, overlapping, touching, or separated. Planes, in addition, may overlap in both opaque and transparent conformations.