The time course of chromatic adaptation

Adaptation to light begins almost immediately, but requires more than I min to reach a steady state. In this study, the change in color appearance with chromatic adaptation is followed for 5 min after the onset of adapting light. Several different adapting fields are used: (I) a full background with a superimposed test vs, a surround outside a contiguous test; (2) a uniform adapting field composed of only long-wavelength light vs. the same long-wavelength field with added "context" composed of other chromaticities. The measurements show that adaptation after 10 s is not nearly complete; instead, color appearance continues to change for more than 2 min. Further, adding chromatic context has a greater effect on color appearance after several minutes of adaptation, compared to 10 s of adaptation, due to a smaller overall change of appearance in the steady state when context is present. (C) 2000 John Wiley & Sons, Inc.