Abstract
Heterochromatic viewing enviroments—where scenes are illuminated by two or more colors of light—are a common tool for experiments studying chromatic adaptation and color (in)constancy. This study presents a new method for separating sensory (retina-based) chromatic adaptation from cognitive mechanisms in a heterochromatic viewing environment. Using a large, bipartite light booth lit by two separate 7-channel LED systems, observers were adapted to uniform and mixed illuminations of simulated illuminant A, illuminant D65, and 12000 K daylight. A psychophysical staircase method determined observers’ white points and their state of sensory adaptation along the daylight and Planckian loci under each heterochromatic or single-color lighting condition. Under heterochromatic conditions, observers’ state of chromatic adaptation fell in between the points of chromatic adaptation when adapted to each individual light source, although there was significant variation between observers. These results suggest that observers’ white points should be individually determined for studies of color perception in heterochromatic environments using methods similar to those used in this study. Further research will then allow us to model how cognitive discounting of the illumination color sits on top of the sensory adaptation measured here.