Color Separations Revisited
CMYK color separation remains prevalent in most print shops, but read on to learn about some powerful alternatives.
Print technology has completely changed the way ink appears on paper and has put the way we prepare graphics on its ear. Color separation is the only area in the workflow that seems to use the same basic methodology across various printing techniques.
Most printers believe that color separations do not exist in the digital printing environment, mainly because we do not see the step (as in film positives) that ultimately creates something we can physically hold in our hands. The perceived effect of the process colors (CMYK) has taken a back seat to color-management philosophies. In reality, though, color separations and color management work side by side to create the graphics we produce for our clients.
Today, files are separated, proofed, and printed primarily with a single printing condition in mind. In a more advanced shop, files are separated, proofed, and printed to a specific proven standard, which has shown to be very successful. The shortcomings of this approach, however, are seldom discussed.
Substrates and color sense
Rarely do we print day-to-day work on the same substrate to which we’ve calibrated the entire process. The only compensation we typically make is when the paper changes from job-to-job. This happens in the pressroom, on a running press or digital printer, in an attempt to match the proof visually. Many times, the proof is only a laser printout.
Rarely do we evaluate specific substrates in hopes of understanding how to print color on them optimally. Today’s technology represents vast advancements in terms of our understanding of color perception, our ability to predict color, the level of achievable automation, and in our ability to print color mechanically and digitally. But sadly, we have lost the ability to create good separations based on color sense.
You may still be skeptical of the variance of values of CMYK within identical files. Allow multiple RIPs or programs to create CMYK values for a specified PMS color. Each method has a different value, be it Adobe Photoshop or Quark XPress. Which is right?
Our clients create the art from illustration software or digital stock-photo Websites and then allow the software and/or RIP to create the color-separation values for print. Separators in the 1980s and 1990s were able to input the data via drum scanners in an attempt to create files that would maximize the printability of the specific output method.
Classic separations include cyan, yellow, and magenta with a skeleton black for depth and more shape in the shadows. A couple of techniques assist in this process: GCR (gray component replacement) and UCR (under-color removal). Most hue value within the CMY color space is produced by the combination of two of the three primaries. The third color, known as the graying component, is designed to move that hue toward gray (decrease saturation).
UCR is the process of eliminating amounts of yellow, magenta, and cyan that add to a dark neutral (black) and replacing them with black ink during the color-separation process. GCR involves the use of black ink to replace CMY values that add to gray all along the tone scale. GCR only adds black to the CMY equivalent of what would print as a gray. Both of these methods can reduce CMY ink usage; however, they can change a graphic’s intent.
Today’s ICC-based technology is excellent at predicting what will happen to color on press, but it relies on this same predictive concept to create a color separation. Said another way, ICC-based separations craft color based on the output of a printing method at some given moment in time, but neither the separations nor the press can ever precisely reproduce that moment again.
The art of optimized printing based upon known print conditions and the art of creating an optimized color separation seem to be lost to us in favor of standardized print conditions. However, this doesn’t mean that standardized print conditions don’t belong in print production—by all means, they do. But once a premium printer can run with the G7 and ISO crowd, what can the business do to differentiate itself through improved color reproduction?
New color-separation software
I was introduced to a color-separation solution at SGIA 09 in New Orleans that merits discussion. The product is called ICE-server, created by FineEye (www.fineeyecolor.com). ICEserver is designed to replace the traditional CMYK color separation. It’s a post-processing methodology used after the native file is built (usually by our client).
FineEye’s focus is aimed directly where the printing event occurs—ink on paper. ICE uses unique Media Map models for every stock a printer sends through the press. The Media Map is the result of quantification of ink interaction with a given paper’s surface structure. Electron microscopy helps create a three-dimensional map of this interaction, which in turn is used to build a table with more than 80,000 individual data points.
ICE claims to be the only technology that approaches color separations by taking ink and paper interaction into such detailed consideration. Secondly, ICE researchers discarded current photomechanical separation constraints and instead looked to human perception. ICE uniquely assigns visual luminosity almost solely to the black plate and then uses the CMY color plates to concentrate on visual hue and saturation. This seems to be similar to the GCR approach, though FineEyes insists the process is vastly different. ICE separations built in this way are said to significantly impact achievable print quality. Finally, development was aimed at creating an automated method for achieving separations similar to what dot-etching craftsmen once produced.
The resulting algorithms, based on human perception and common-sense color editing, instruct ICE how to best distribute CMYK ink in a given file to print color. ICE uses the Media Map and its internal knowledge of CMYK ink distribution to understand how a given file will best print on a particular paper stock. The software then creates a CMYK separation that’s optimized for the printer. The result is FineEye’s claimed increase of up to 20% in gamut, most visually noticeable in saturated colors, as well as faster press startup, improved print stability, and reduced problems in trapping—all delivered with a reported 20% average reduction in ink consumption.
In my brief analysis, I believe this type of technology represents ink savings, color balance,and increased color gamut—all of which are valuable in screen and digital.
The state of separations
The color separator’s domain was to offer expertise while creating prepress solutions. That value-add was very real, though it initially appeared to be a bit of smoke and mirrors. Then came the reality of digitally created art without scanning images. Printers have since met the creation and alteration of graphics files to maximize printability with trepidation. Generating modified color separations to increase color consistency during printing, improve color gamut, and decrease ink costs is the perfect storm. Thanks to new processes and technologies, predictable transformation appears possible.
The opinions and recommendations expressed in this column are Mr. Mandel’s and not necessarily those of Screen Printing magazine.
Rick Mandel is the owner and president of the Mandel Company of Milwaukee, WI. He also serves as CEO of the company’s Screentech Division, a 115-year-old graphics firm that specializes in large-format color separations for commercial printing companies, as well as digital production of large-format graphics. Mandel is a member of the SGIA and the Association of Screen Printing Sciences.