If you’ve seen promotions about our upcoming Optimizing Digital Color from Your Digital Press workshop and wondered how this training would benefit you on the job, take a lesson from the Publications team here at Printing Industries of America. We recently got some firsthand experience with how color reproduction changes when a job shifts from the offset press to the digital press, and our best resource was workshop leader Dave Dezzutti.
So, how did we get there and what did we learn from the experience?
In the past, at Printing Industries Press we have always produced our color-related titles on a lithographic press because accurate color reproduction is critical when discussing the science and control of color. But over the years most of our titles have migrated to digital short-run production, and our most recent book, Color Printing Excellence, made that transition to digital printing as well.
Knowing it would be printed on the iGen4 production press, our digital production staff assured us the press would be able to handle the color reproduction to meet the needs of this topic. But we did need to do a little behind-the-scenes work to make sure we got there on a few of the more color-critical images.
Color Printing Excellence developed from the need to update Color and Its Reproduction, Third Edition, which had been printed on an offset press. That meant a lot of the images used in Excellence were picked up from the original text, and those images had been optimized for offset production. As the editor worked on the layout and proofs for review throughout the editorial process, he noticed there were inconsistencies between the images, such as the digital versions being darker than the earlier offset printing, and these were differences that went beyond the paper used.
We’re lucky to be able to turn to our in-house experts and staff consultants when problems like these surface. Technology and Research Analyst Dave Dezzutti, who is also the instructor of the Optimizing Digital Color from Your Digital Press workshop, was able to take a look at our images, troubleshoot and diagnose the issues, and walk us through the solutions.
Some of the problems and necessary adjustments included:
- Images appeared darker when printed on digital press. The adjustments needed here were minimal and involved lightening the image with some middletone adjustments in Adobe Photoshop. Dave indicated that the darkening is a probable result of the GCR (gray component replacement) present in production inkjet presses.
- Overlap of color. In one sensitive graphic it was important that the dots in a simulated screen pattern did not touch. However, despite the editor’s great care, while working in Adobe Illustrator, to allow a reasonable amount of white space between each dot, in the digitally printed proofs, the dots still bumped up against each other unacceptably. Dave recognized this problem as resulting from the trapping that was built into the system. To produce this critical image, he advised printing this page separately, with trapping turned off, and tipping the page in to the book during binding.
- Color builds could not reach 100% density. This same image included a build of process colors (cyan and magenta) compared against the process colors themselves. These colors would have been produced as a solid color on an offset press, but in the digital proof, when inspecting the image with a loupe, the color was not solid. Dave explained that this is because the digital press “builds” color, whereas an offset press would print straight cyan and magenta dots because they are the primary print colors. To satisfactorily produce the image, we had to turn off trapping and, in the right hand image, reduce the density of the individual cyan and magenta to 85% to more closely match the left-hand dots when viewed through a loupe. This allowed the values to be exactly the same, which is what the illustration, used as a demonstration of additivity failure and proportionality failure, demanded.
For a team that doesn’t have a lot of color management experience, Dave was a valuable resource. His years of hands-on experience enabled him to quickly recognize problem areas and then walk us through the necessary steps to fix them—easily translating his technical know-how to fit our knowledge level.
What did we take away from the experience?
- When working on a cross-process project, it’s important to be aware of the restraints of the digital process. Just because an image reproduced accurately on press once doesn’t mean it will reproduce well again when the output changes.
- We also have a better grasp of what the terminology means when it comes to adjusting color on an image. The process for “lightening” an image, for example, isn’t necessarily intuitive, and you could end up wasting time making the wrong adjustments.
- We also now have a clearer understanding of what could be wrong when color images don’t reproduce as expected on a digital press.
You, too, can learn these kinds of practical lessons and more from Dave at the Optimizing Color from Your Digital Press workshop, May 21–22, 2013, at Printing Industries of America headquarters in Sewickley, PA. For more information, visit www.printing.org/training.