Abstract

It has been suggested by Alpern and Neitz and Jacobs that the L and M cone pigments are not identical for all normal observers. We have examined this hypothesis by comparing the color matches for standard wavelengths of 560, 570, 580, 590, 600, and 610 nm and mixture primaries of 546 and 650 nm in bleached and unbleached conditions. For a 590-nm standard and 4° field, we found that the distribution of matches for our observers was broader for males than females but only at low illuminances. However, when the high illuminance color matches of the experienced observers are plotted, the data fall clearly into two groups of four observers each. That is, the data are separated by an R/G ratio of a 0.05 log unit in bleached conditions. The difference between these two groups cannot be due to differences in the amount of pigment bleached, since there is no significant difference in the half-bleach illuminances. The difference between groups is less distinct in unbleached conditions. A difference is also present for the 610-nm standard, which indicates that the difference cannot be due to lens density.

© 1987 Optical Society of America