Imperfect as a color bar or grayscale may be, I would put in an ardent plea for their inclusion in all digital scans, whether of old rescanned transparencies or new scans of artworks. I speak on behalf of the publishers and printers who have been left with no visual cues to guide color correction on press.
The quality of color printing from digital scans fluctuates wildly because the skilled eyes of editors and book designers have no guide. However good the embedded digital information may be, there is no substitute for looking at a color bar and grayscale to see if the press proof is running too warm or cold, too contrasty, or too saturated. Not to mention that digital presses are calibrated as variably as computer monitors, and most printers use standard settings. Every art publisher I know is deeply unhappy with the shift from transparencies to digital scans for this reason. We may love the financial savings in using digital files of art images at the design and layout stage, but we have completely lost control of the color process, and are dependent on the guesswork of printers. To be clear: The grayscale and color bar are normally not guides for the printer but for the editor and/or designer who checks the proofs. The color correction is made by them, and the printer follows those directions. Printers typically do not consult the color bar or grayscale, as they use their own standard settings at the proof stage. Comparison of a color proof with the original artwork is a vanished concept. Today's production budgets, schedules, and methods have done away with that step, except perhaps within a museum's own publication program. The digital scans made of artworks by museums are used not only internally, but also by myriad outside publishers. I will dodge the interesting but unresolvable question of what publishers mean by "accurate" color printing. To quote Justice Potter Stewart in another context, we know it when we see it. Regards, Eve Sinaiko Director of Publications College Art Association