In recent years the differences in image quality of digital printers relative to offset lithographic presses have been becoming ever subtler. In 2007, experimentation was conducted within the Printing Industry Center at the Rochester Institute of Technology examining this difference. It was found that there were significant differences in the perceived value of prints made on digital versus offset printing equipment. Prints on coated media made on offset equipment were generally preferred, while the prints on uncoated media made on digital printers were frequently assigned higher values. The results of this experiment were possibly compromised by the reality that there were unintended shifts in the color balance of the prints made on some of the digital equipment relative to the offset reference prints that the participants in the study were asked to disregard.
The present study was conducted to examine the effect, if any, of these unintended color shifts and to further probe the effect of the media on the perceived image quality differences between high-end digital presses and offset lithography. The impact of observer image evaluation skill on the perceived image quality differences was also examined. The experimental results suggested that the color balance shift had minimal impact on the perceived image quality differences, though contrast played a significant role. The media also had a strong effect on perceived quality. Unsurprisingly, skilled observers tended to rate images more critically than unskilled participants, though this effect was only statistically significant for photo-based images on uncoated paper.