Arguments are put forward to explain the basic facts about colour vision in the frame work of a zone theory, a combination of the Young-Helmholtz and the Hering theory. Data on wavelength discrimination in particular as a function of luminance, necessitate to assume separate mechanics for red-green and for yellow-blue discrimination. Some psychophysical data on the other hand, like the Stiles-Crawford effects and those on chromatic adaptation, give reason to assume three different visual pigments in the receptors, of which the spectral absorption curves and the densities can be derived.
Samenvatting