Rapid chromatic adaptation and the sensitivity functions of human color vision.

Previous studies have shown that the spectral sensitivity curve of the cones, in the dark-adapted eye, displays three maxima and that these are indicated even more clearly when the foveal test stimuli are superimposed upon colored adapting stimuli. These maxima are believed to be the result of at least three underlying sensitivity functions related to the “fundamental response curves” of human color vision. By delivering foveal, monochromatic test flashes only 0.05 sec after the onset of colored adapting stimuli, these maxima are further enhanced, and very large distortions of the usual spectral sensitivity curve result. On the assumption that the over-all sensitivity curves for five conditions of adaptation are the sum of four underlying sensitivity curves (with maxima at approximately 430, 530, 570, and 610 mμ), a satisfactory fit of the experimental data is obtained which appears to support a four-component theory of color vision.