Color Fluctuations of Displayed Color Due to Dot Shifts in Dot Printing

Abstract

In images constructed by binany dots, spatical shift of individual dot is considered as a factor of degrading image quality, and especialy, it causes color fluctuations in resulted images. In this paper, the relation between dot-shifts and color fluctuations of the image has been quantitatively examined by computer simulation. For several typical dot patterns, color fluctuations derived from randum shifts of dots were calculated with and without UCR and plotted on UCS chromaticity diagram, and following conclusions were obtained. (1) Effect of dot shift in dot image on displayed color depends on the dot pattern type used. (2) Color fluctuations in print of Bayer type without UCR are larger than that of other types, but smaller with UCR. (3) As compared with tricolor printing, UCR puts a restraint on fluctuations of brightness of displayed colors, provided that dot shifts occur in each ink plate, but increase fluctuations of brightness, when dot-shifts occur in each dot.