Color constancy and color rendering: Concomitant engineering of illuminants and reflectances

A strategy for cooperative illumination and reflectance design to produce color‐stable environments includes reduction of metamerism and paramerism, followed by attempts at color constancy. Given a model of color constancy based on linear basis‐function expansions of illuminant and reflectance spectra, all these goals could be served by designing reflectances and illuminants to inhabit certain compatible subspaces of spectral functions. Such linear models suggest two new indices of metamerism, one for designing illuminants and the other for designing reflectances. Implications are noted for designing color atlases. Finally, a physiological model of color constancy is described that is nonlinear and hence may add challenge to the concomitant design.