Reflectance model for recto-verso color halftone images

Abstract

In the color reproduction process, accurately predicting the color of recto-verso images and establishing a spectral reflectance model for halftones images are the great concern project of imaging quality control field. The scattering of light within paper and the ink penetration in the substrate are the key factors, which affect the color reproduction. A reflectance model for recto-verso color halftone prints is introduced in this paper which considers these factors. The paper based on the assumption that the colorant is non-scattering and the assumption that the paper is strong scattering substrate. By the multiple internal reflection between the paper substrate and the print-air interface of light, and the light along oblique path of the Williams-Clapper model, we proposed the color spectral reflectance precise prediction model of recto-verso halftone images. In the study, we propose this model for taking into account ink spreading, a phenomenon that occurs when printing an ink halftone in superposition with one or several solid inks. The ink-spreading model includes nominal-to-effective dot area coverage functions for each of the different ink overprint conditions by the least square curve fitting method, so the functions for physical dot gain of various overprint halftones are given. This model provided a theoretical foundation for color prediction analysis of recto-verso halftone images and the development of image quality detection system.