Accuracy of color scission for spectral transparencies.

When surfaces are overlaid by a transparent filter, color scission refers to the perceptual separation of the colors of the image into the colors of the underlying surface and the color of the overlaying layer. We used filter matching to measure the accuracy of color scission for simulated physical filters and materials. Standard filters were placed on various sets of chromatic materials and match filters on achromatic materials. In the majority of cases, filter matching was close to veridical. The spectral effects of filters are complex, but with respect to the visual system, they can be closely approximated by 3-D affine transformations of cone absorptions or chromaticities. Veridical filter matches can be predicted by neural strategies that match ratios of mean cone absorptions or match mean chromatic contrasts between filtered and exposed regions. However, when the shape of a filter transmittance differed significantly from the shapes of background reflectances, the overlaid region had lower saturation than the surround, and filter matches had broader transmittance spectra than veridical.