Effects of chromatic adaptation on color discrimination and color appearance

Abstract

Color discrimination and color appearance were examined at a number of chromaticities along an equal luminance line running from red to green as a function of adaptation to several lights along the same line. Like K. J. W. Craik's results for brightness discrimination [ J. Physiol. 92, 406–421]. color discrimination proved best for chromaticities nearest the adapting light with a worsening of discrimination (relative to neutral adaptation) for more distant chromaticities. This result is explicable in terms of a sliding of the “working range” of red-green opponent cells along an axis of chromaticity. Consistent with this interpretation are the systematic changes in color appearance brought about by preexposure to chromatic light. An ancillary part of the investigation revealed that a flickering adapting light produces lesser adaptive shifts than steady light of the same time average luminance. This latter result rules out the possibility that photopigment bleaching, under these conditions, plays more than a minimal role in controlling the sensitivity of the cones or more proximal neurons.