The Stiles-Crawford colour change

Abstract

To obtain the Stiles-Crawford colour change, the absorption of guided and unguided light by a cone outer segment as a function of the angle of incidence is estimated. The model is specified in two ways: the HE1,1 model, based on a waveguide modal analysis, and the geometrical optics model. The measurements by Stiles (1937) are fitted with reasonable success, both for the intensity effect and for the colour change, using the phenomenon of selfscreening to explain the colour change.