Color constancy from chromatic adaptation

While viewing a mondrian in a color constancy task, a subject adapts to the stimulus as well as the other objects in the mondrian. As the adaptation levels due to the mondrian are uncontrolled, the amount of the constancy generated by chromatic adaptation to the stimulus and surround is unknown. The first two experiments measure hue and saturation constancy under natural daylight illuminants in a scaling task due to chromatic adaptation to the illuminant. Both hue and saturation constancy are found to be nearly complete from chromatic adaptation to natural illuminants via a scaling task. A third experiment compares hue constancy generated by chromatic adaptation to the illuminant with the amount of hue constancy generated by a mondrian surround to the stimulus and maintaining a stable state of chromatic adaptation. Chromatic adaptation once again generates very strong constancy while the presence of a mondrian under a controlled adaptation condition seems to do little to promote constancy. These three experiments suggest that chromatic adaptation is an important part of maintaining color constancy and that the most important constancy cue from a mondrian may well be a stimulus to which the visual system can adapt.