The wavelength difference limit Δλ below which a complete color fusion takes place was investigated for the fields of 10° and 2° arc of visual angle by inputting stimuli of different wavelengths and of the same brightness into the respective eyes. The limit varied from 15 nm to 100 nm depending upon the wavelength employed with two minima, when plotted along the spectrum, exhibiting a saw wave shape of Δ-λ curve. The results were interpreted according to two ways: the color difference hypothesis and the opponent-colors theory. The former assumes the fusion limit to be determined by the color difference introduced between two eyes, and the latter hypothesizes the binocular fusion to cease whenever mutually opponent color components, such as red and green, are perceived in the respective eyes. © 1980.
Ikeda, M., & Nakashima, Y. (1980). Wavelength difference limit for binocular color fusion. Vision Research, 20(8), 693–697. https://doi.org/10.1016/0042-6989(80)90094-2