Abstract
Analyses of measured hue-naming functions were used to infer the direction and magnitude of Bezold-Brücke hue shifts. Hue-naming functions were obtained in the fovea and at 10° temporal retinal eccentricity with different stimulus intensities (0.3–3.3 log td), stimulus sizes (.25°–3.0°), and adaptation conditions (rod bleach, no-rod bleach), in order to manipulate the underlying receptor signals. Hue ratios computed from the hue-naming functions were used to simulate Bezold-Brücke hue shifts measured under the traditional bipartite-field procedure. Computed Bezold-Brücke functions based on foveal data display the traditional pattern of wavelength shifts, i.e., with increasing stimulus intensity, longer wavelengths appear more yellow and shorter wavelengths appear more blue. The functions derived from the peripheral retinal data differ from the foveal functions. Our results show that stimulus parameters and adaptation conditions influence the hue-naming functions and thus the degree and direction of the derived Bezold-Brücke hue shifts. Observed differences in the Bezold-Brücke foveal and peripheral hue shifts will be discussed in terms of rods, photoreceptor density and distribution, and photopigment optical density.