After-Images in Chromoluminant Space

Prolonged viewing of colored surfaces produces the sensation of after-image, which results in a complementary color to the one physically presented. Retinal pigment bleaching along with neural factors is supposed to be the basis of after-images. We have developed a computer-aided technique for matching the after-image complementary hues, in which the stimulus is composed of twelve circularly placed colored patches. One of the patches disappears in the clockwise direction for 300 ms, while others are static. The perceived after-image color is matched in the central patch. Colors of the stimuli are defined in the DKL opponent color modulation space for isoluminance conditions. In the experiment, no significant changes in brightness were identified for after-image complementaries. We observed elongate saturation along the diagonal axis (close to 135°). To fit the saturations of complementary colors the sum of sine functions is proposed.