This chapter briefly discusses some of the issues in color perception and color representation that are important for computer graphics. Color perception and color representation are complicated topics, and more in-depth information can be found in references such as (Berns, Billmeyer, and Saltzman, 2000); (Jackson, MacDonald, and Freeman, 1994); (Foley et al., 1990); Volume I of (Glassner, 1995); or (Hall, 1989). Also recommended is the short, readable introduction to the physics of color and the physiological aspects of color perception in (Feynman, 1989). Some more detailed recommendations for further reading are given at the end of this chapter.

The first section of this chapter discusses the physiology of color perception and its implications for computer graphics. The second, more applied section discusses some of the common methods for representing color in computers.

Color Perception

The basic theories of how humans perceive color were formulated already in the nineteenth century. There were two competing theories of color perception: the trichromatic theory and the opponent color theory. These two theories will appear contradictory at first glance, but in fact they are both correct in that they are grounded in different aspects of human color perception.

The Trichromatic Theory of Vision. The trichromatic theory was formulated by G. Palmer, in 1777 and then again by T. Young in 1801; it was extended later by Helmholtz. This theory states that humans perceive color in three components: red, green, and blue.