Preferred lightness and chromatic image contrast reproduction

In this study, the image preference as a function of lightness and chromatic contrast of images produced on an ink-jet printer is examined. The purpose is to develop image manipulation rules, useful in the development of printer algorithms to produce images that are preferred by viewers over images that have been printed without application of these rules. Five images are used during the psychophysical experiment, two business graphics and three pictorial, processed in three different ways in RLAB color space, once having only the tightness contrast varied, then only the chromatic contrast, and finally both lightness and chromatic contrast varied. The results showed that for the graphics images seen without a CRT original used for comparison, the mean preference was an increase in lightness contrast, while with an original available for comparison, the mean preference indicated a decrease in both lightness and chromatic contrast. For pictorial images, in the first phase of the experiment the mean preference was an increase in both lightness and chromatic contrast, and after comparison, a decrease in lightness and simultaneous decrease in lightness and chromatic contrast are the most preferred