In this paper, we will report the hardcopy psychophysics study on the human visual perception on banding in the secondary colors of a polychromatic EP process. The goal of the work is to develop appropriate process control metrics for each primary color plane. Our previous softcopy psychophysics experiments have shown that reducing the banding in each primary color layer to under the human visual system (HVS) threshold does not guarantee absence of bandings in secondary colors. It was also shown that the relative phase between the banding patterns on the primary color layers is an important factor for the perceptibility of banding in the secondary colors. The hardcopy experiment results substantiate the same threshold conclusion as that of the softcopy experiments. Due to the other printing artifacts as well as the intrinsic bandings in the hardcopy printout, the phase results are inconclusive for the hardcopy experiments. The embedded process control system used to generate the controlled stimuli on each primary color plane as well as the relative phase between the two primary color layers is also discussed.
Mu-Chih Chen, George T.C. Chiu, "Hardcopy Characterization of Banding in Secondary Colors in Color Electrophotographic Processes" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP22), 2006, pp 502 - 505, https://doi.org/10.2352/ISSN.2169-4451.2006.22.1.art00047_2