An empirical explanation of color contrast

For reasons not well understood, the color of a surface can appear quite di fferent when placed in different chromatic surrounds. Here we explore the p ossibility that these color contrast effects are generated according to wha t the same or similar stimuli have turned out to signify in the past about the physical relationships between reflectance, illumination, and the spect ral returns they produce. This hypothesis was evaluated by (i) comparing th e physical relationships of reflectances, illuminants, and spectral returns with the perceptual phenomenology of color contrast and (ii) testing wheth er perceptions of color contrast are predictably changed by altering the pr obabilities of the possible sources of the stimulus. The results we describ e are consistent with a wholly empirical explanation of color contrast effe cts.