Redness from short-wavelength-sensitive cones does not induce greenness.
According to opponent-colors theory, a reddish surround induces greenness in a central test field. Color-appearance measurements verify this with a long-wavelength reddish surround (660 nm) but not with a short-wavelength reddish surround (440 nm). Surprisingly, a short-wavelength reddish surround shifts the appearance of a test toward redness. Four possible explanations are: (1) stray light from the short-wavelength reddish surround falls in the test area; (2) receptoral sensitivity changes overwhelm induced greenness from the surround; (3) a neural process of assimilation, rather than contrast, to the surrounding light; and (4) short-wavelength-sensitive (S) cones do not contribute to induced redness/greenness. Chromatic cancellation experiments confirm the fourth explanation. There was no change in induced redness/greenness when quantal absorption by only S cones in the surround was varied by 30-fold (using tritanopic metamers), even though varying stimulation of S cones strongly affected the color appearance of the surround. The redness induced by a short-wavelength surround is accounted for by opponent chromatic induction mediated by only middle- and long-wavelength-sensitive cones.
Shevell
S K
SK
Department of Psychology, University of Chicago, IL 60637.
D003118:Color Perception / Q000502:physiology*; D003623:Dark Adaptation / Q000502:physiology; D006801:Humans; D008027:Light; D008959:Models, Neurological; D010775:Photic Stimulation; D010786:Photoreceptor Cells / Q000502:physiology*; D013053:Spectrophotometry