Abstract

The color constancy hypothesis predicts that the color appearance associated with a vector of cone responses shifts as the visual system adjusts to changes in illumination. We measure color appearance using a classification paradigm¹ and verify that changes in illumination do induce shifts in color appearance. Because there are many illuminant spectral power distributions, it is not possible to measure the shifts induced by all of them. If color constancy is to be a useful guide to the prediction of color appearance, the shift induced by any illuminant must be predicted by the shifts induced by a small set of illuminants. We show that when the set of surfaces encountered by the visual system is restricted, the filtering action of the cone spectral responsivities strongly limits the illuminant variation that can be detected at the level of the cone responses. The illuminant variations that are not filtered by the cones form a linear subspace. We test whether the shifts induced by illuminants in this subspace can be predicted from the shifts induced by each of the subspace’s basis illuminants.

© 1988 Optical Society of America