Abstract

The relative numerosity of the long-wavelength-sensitive and middle-wavelength-sensitive cones and the red-green color appearance, as assessed by means of unique yellow, are stable from fovea to midperiphery. As foveal tests decrease in size, unique yellow progressively shifts toward longer wavelengths, favoring a model of red-green opponency carried by cells whose centers receive input from either L or M cones and whose surrounds receive mixed contributions from both. Individual differences in unique yellow over a 20-nm range and the relative numerosity of L and M cones can be linked by means of this model, suggesting that the relative number of L and M cones is a factor that regulates individual variations in red-green color appearance. © 2000 Optical Society of America.