The ability of color-deficient observers to discriminate between
illuminant changes and surface-reflectance changes in a scene was
tested with natural and Munsell reflectance spectra. To avoid the
confounding effects of spatial structure, stimuli were simulations of
Mondrian-like colored patterns, presented on a computer-controlled
color monitor. Protanopes performed less well than normal trichromats,
regardless of the type of reflectance spectra, but they were least
disadvantaged with patterns comprising reflectance spectra drawn from
urban and rural scenes, more characteristic of the natural
environment.