Foveal photopigments

The relative rates of absorption of quanta per unit of energy for the various wavelengths can be assessed for the human red, green, and blue photoreceptors by assuming that the responses generated by a photoreceptor are proportional to the rate of absorption of quanta. We start by selecting three points on the color mixture diagram to represent the fundamental colors. The mixture diagram is then transformed to a constant luminance diagram in which the fundamental colors serve as primaries. The V(lambda) values are then multiplied by the chromaticity coordinates (r, g, and b) to determine the response curves of red, green, and blue cones. The values of V(lambda)r, V(lambda)g, and V(lambda)b are divided by the transmittance of the ocular media and the wavelength to give the relative absorptions. No allowance has been made for self-screening or population densities. I have used the Judd (V(lambda) curve and the Wright-Guild mixture data. I have found three fundamental colors which yield predictions for the absorption curves of the photopigments of the foveal cones which conform well to the absorbance curves measured directly.