Wavelength-specific brightness contrast as a function of surround luminance

We studied the effect of a monochromatic surround of varying wavelength on the brightness of five monochromatic test fields using a binocular matching technique. The results showed that brightness reduction of the test field was greatest when the wavelength of the surround was similar to that of the test field, particularly within the three wavelength regions of red, green and blue. In addition, the slope of brightness reduction with increase in surround luminance was found to vary as a function of surround wavelength: also, the wavelength-selective brightness reduction was much more prominent for the higher luminance surrounds. A two-factor model with channel-specific and channel-nonspecific lateral inhibition is proposed.