Colored pencil on paper, 6.5" x 10"
When colors are chosen and organized in particular ways, they can give a three-dimensional sense to a picture. Colors that are complementary to their background tend to "pop out" or to occupy a space in front of the background.
Yellow is a high-value warm color and at its most saturated, it appears to "advance" or be closer to the viewer. Violet is a cool color and at low intensity it tends to "recede." In this drawing, the triangle of bright yellow appears to be floating in front of its background. The background of the various greyish-browns resulting from mixing the single spectrum-yellow and spectrum-violet seems to fall back behind that central rectangle.
Knowing how colors behave in combination with other colors is vital when an artist wants to emphasize an area of an image, or wants to develop a composition that leads the viewer's eye through the picture.