Some dynamic features of colour vision.

Abstract These experiments are analogous with classical studies of threshold luminance perception, with wavelength changes replacing intensity changes. Throughout the spectrum the shapes of the sensitivity-vs.-frequency curves for the perception of wavelength modulation are quite different from the shapes of the analogous (De Lange) curves for luminance modulation. These curves are interpreted as descriptions of the different attenuation characteristics of the neural mechanisms which underlie the perception of threshold changes of stimulus wavelength and intensity respectively. The classical bipartite-field method gives little information as to the dynamics of wavelength discrimination. We report that the shape of the wavelength discrimination curve is a function of stimulus repetition frequency. Although the yellow minimum is little affected, the blue-green minimum shifts from 500 nm to below 480 nm when stimulus frequency is reduced from 5 Hz to 0.5 Hz. Tentative attempts are made to use the data as fresh tests of colour vision. Our data indicate that dynamic wavelength discrimination curves cannot straight forwardly be related to CIE data.