Investigation of Workflows for High Quality, Fine Art Black White, Digital Publishing

摘要

Despite the advent of color printing, for many artists and photographers, a high quality black and white image is still the preferred output medium for their fine art work. Classically, the highest quality black and white photography books are printed using offset presses equipped with multiple gray inks for rich, smooth and detailed prints. Similar quality is difficult to achieve on modern digital presses, where the output production is typically limited to a standard 4-color (CMYK) ink set. HP Indigo digital presses have the ability to print with up to 7 different inks. While the typical use of the additional 3 channels is for custom colorants deployed in spot color applications, they also have the potential to be deployed for fine art black and white printing using multiple gray inks similar to those deployed in conventional offset presses. Such custom, black and white ink based workflows, deployed on digital presses, have the added advantage of being able to print short-run productions which are very desirable in limited-edition, fine art reproduction applications.rnThis paper summarizes some general results of experiments performed at HP Labs, along with work-in-progress in attempting to produce high-quality reproductions of a silver halide portfolio on an HP Indigo digital press at RIT using 2 different workflows -one using standard 4 color (CMYK) inks and the other using custom mixed gray inks (3 grays and black - hence referred to as GGGK). While acceptable results were achieved using the CMYK method, it was found that the GGGK method produced noticeably better results. However, the transfer curves and separations could benefit from some additional mathematical rigor. There was some unacceptable posterization in areas of density transition in some images. The workflow is being refined to fix this problem and new results will be reported later.