Color Reproduction Quality Metric on Printing Images Based on the S-CIELAB Model

The just-perceived color difference in a pair of printing images, the reproduction and its original, has been confirmed, subjectively by a paired-comparison psychological experiment and objectively by the S-CIELAB color quality metric. For one color image, a total number of 53 pairs of test images, simulating a number of varieties in C, M, Y, and K ink amounts, were produced, and determined their corresponding color difference recognizing probabilities by visual paired-comparison. Also, the image color difference Delta Es values, presented in the S-CIELAB model, for each pairs of images were calculated and correlated with their color difference recognizing probability. The results showed that the just-perceived image color difference Delta Es, when 0.9 color difference recognizing probability being considered as the just-perceived level, was about 1.4 Delta Eab units for the experiment image, being the image color fidelity threshold parameter.