Light scattering and ink penetration effects on tone reproduction

Light scattering, or the so-called Yule-Nielsen effect, and ink penetration into the substrate paper play important roles in tone reproduction. We dev elop a framework in which the influences of both of these effects on the re flectance and tristimulus values of a halftone sample are investigated. The properties of the paper and the ink and their bilateral interaction can be parameterized by the reflectance R-p(0) of the substrate paper, the transm ittance T-i of the ink layer, the parameter gamma describing the ink penetr ation, and (p) over bar describing the Yule-Nielsen effect. We derive expli cit expressions that relate the reflectance of the ink dots (R-i), the pape r (R-p) and the halftone image (R) as functions of these parameters, We als o describe the optical dot gain as a function of these parameters. We furth er demonstrate that ink penetration leads to a decrease in optical dot gain and that scattering in the paper results in the printed image's being view ed as more saturated in color. (C) 2001 Optical Society of America. OCIS co des: 100.7810, 290.7050.