Evaluation of ink optimization technology in offset color printing

Abstract

This research relates to ink optimization technology as used in prepress workflows. A primary objective of ink optimization processing is that cyan, magenta, and yellow (CMY) inks can be replaced by a given amount of black (K) ink, appropriately chosen to create the same visual color as the original but with less total ink coverage. Ink optimization technology incorporates aspects of under color removal (UCR) and gray color replacement (GCR) technologies in black channel generation, but extends these concepts to include ink savings, press stability, and workflow integration. Ink optimization systems are used to process images to create color separations of RGB to CMYK or color re-separations, from CMYK to CMYK. This technology is currently used in all areas of color printing, but in particular in relation to web and sheet-fed offset lithographic printing, where high-quality images and long press runs offer the opportunity for maximum ink savings. This research establishes evaluation criterion and benchmarking statistics for ink optimization technologies. The tests show that ink optimization works-the systems are able to process files in real time, new optimized files have lower CMY values, reduce ink consumption on press, are more stable on press, yet files still retain colorimetric accuracy to the original and do not introduce imaging artifacts. © 2010 Society for Imaging Science and Technology.