ABSTRACT
The Hering model explains, for example, the perception of the color brown, which results only when orange or yellow is surrounded by a brighter color. It also accounts for the phenomenon of color constancy, in which the perceived color of an object remains unchanged under differing ambient light conditions provided background colors are available for comparison. Color vision is absent in many species, including cats, dogs, and some primates, as well as in most nocturnal animals, since cones are useless in low light. Psychophysical experimentation yields a complex, redundant map between spectrum and perceived color, or hue, including not only the standard red, orange, yellow, green, and blue but hues such as pink, purple, brown, and olive green that are not themselves in the rainbow. The Hering model explains, for example, the perception of the color brown, which results only when orange or yellow is surrounded by a brighter color.
