Color desaturation in the periphery is explained by general mechanisms of contrast sensitivity and constancy

Colors appear less saturated in the visual periphery than in the fovea. We revisit this well-known phenomenon by characterizing parafoveal perceived contrast as a function of size. Observers (N = 20) matched the perceived contrast of a parafoveally presented comparison disc (2°-0.33°) to a standard 2° disc. For chromatic stimuli, perceived contrast decreased with decreasing size. A similar decrease in perceived contrast occurred for salience-equated luminance-defined discs. Loss of perceived contrast reduced as standard stimulus contrast increased, in line with contrast constancy theory, which predicts constant appearance for stimuli that are sufficiently distant from threshold. Since chromatic contrast sensitivity is reduced away from the fovea and color gamut has a lower range compared with luminance gamut, contrast constancy for color is unachievable within the monitor gamut for small isoluminant patches. Blurred edge discs had substantially reduced perceived contrast, reflecting the important role played by higher spatial frequency channels in defining contrast salience for luminance and color alike. In conclusion, the appearance of color and luminance in the periphery is affected similarly, implying that the process is governed by general laws of contrast sensitivity and constancy. (PsycInfo Database Record (c) 2026 APA, all rights reserved).