Unique hue loci were measured for four observers in the fovea and at 20-deg temporal eccentricity as a function of test size. Eccentric measurements were made on the cone plateau following a rod bleach. The results indicate that unique yellow remains approximately invariant with respect to test size and retinal eccentricity, whereas unique blue and unique green shift to longer wavelengths with increasing test size. The locus of unique blue in the periphery reaches an asymptote at approximately the same wavelength as that from the foveal measurements, whereas unique green measured in the periphery is consistently at shorter wavelengths than in the fovea. In general, the data are best described by a model in which the short-wavelength-sensitive cone input to the two opponent-color channels decreases with decreasing test size and increasing retinal eccentricity.
© 1995 Optical Society of America
Original Manuscript: September 14, 1994
Revised Manuscript: January 3, 1995
Manuscript Accepted: January 5, 1995
Published: June 1, 1995
Janice L. Nerger, Vicki J. Volbrecht, and Corey J. Ayde, "Unique hue judgments as a function of test size in the fovea and at 20-deg temporal eccentricity," J. Opt. Soc. Am. A 12, 1225-1232 (1995)