Change in hue with rod intrusion during dark-adaptation

Abstract

Following light-adaptation, the sensation of hue of a monochromatic light of 620 nm was found to remain invariant for several minutes during the cone-plateau period. Eventually, however, the hue of the 620 nm test light changed toward yellow. The change in hue toward yellow started when the threshold of the rods had reached a certain intensity level above their absolute dark-adapted threshold, irrespective of the intensity of the light-adaptation and thus of the rate of the dark-adaptation of the rods. It is concluded that the change in hue toward yellow during dark-adaptation is an effect of rod intrusion.