Wavelength Discrimination in the Presence of Added Chromatic Fields*

The purpose of this research was to investigate the effect of adding various luminances of monochromatic light to a wavelength-discrimination target. As the additive luminance was increased, the size of the discrimination step increased. With a 650-nm added field, the wavelength-discrimination functions showed asymmetrical displacement, with comparatively little change for wavelengths below 480 nm. With a 435-nm addition, the wavelength-discrimination steps increased for all wavelengths. With a 578-nm addition, they increased in the spectral region 500–600 nm.