Print Control Wizard Automates Color Experts’ Roles
Consider a world where there is a growing shortage of color geeks in the flexographic industry. The existing experts are retiring, and taking with them an enormous knowledge pool and well-honed set of skills.
Consider this, and you may find yourself at the same conclusion Esko found itself not too long ago. “The current flexographic color experts are reaching retirement age and it’s very hard to find replacements in today’s labor market,” admits Rory Marsoun, director business development – flexo, Americas at Esko. “Very few school graduates come out of education seeking work in the flexographic printing industry.”
One answer to this problem, in any industry, is to lean on computers, automation and other modern technologies—even robots—to fill the void left by a lack of skilled workers. Esko’s solution—to capture domain expertise and deep knowledge in a wizard-driven software application which can then be used by a prepress novice—is not a physical robot, but if it were, it would be more Wall-E than Terminator.
“Esko Print Control Wizard (PCW) offers a standardized approach to screen and curve creation for consistent, high-quality output,” he explains. “It was developed in response to a call from the flexographic printing industry to simplify the implementation of screens and dot gain curves in the reprographics process.”
A response to that response came in the form of a 2019 FTA Technical Innovation Award for PCW, the only winner in the Prepress – Graphics category. “Of course, Esko is honored to receive an FTA Technical Innovation Award—It is the preeminent global technology award for flexo printing,” Marsoun exclaims. “We’d like to think this is confirmation that we are on track with our journey of continuous improvement in the speed and quality of flexographic printing.”
Programming Expertise
As the saying goes, imitation is the sincerest form of flattery. Before PCW could imitate color experts, prepress professionals and plate makers who possess decades of experience, it had to learn from them, to understand concepts like screening, color management and a wide range of variables.
Development began with what Marsoun describes as a “user deep dive experience process,” where Esko plotted out plate making difficulties, talked with its own employees and explored the utility of the solution with its customers. The company then built a wizard-based tool to organize a press calibration standard and, from that standard, used automated measurement data from the press to generate custom screens and curves needed to produce plates. Marsoun says the resulting system “builds upon the mathematics of operator input and screening, and light source output.”
Esko spent more than two years beta testing the combination PCW concept and new screens with nearly two-dozen customers. Background data and reference charts were created for every print item that could affect the final result. The company worked closely with plate manufacturers from around the world to build and maintain an accurate database of specifications.
For a user, that data crunching is hidden underneath an interface familiar to anyone who has ever had to fill out a form on a website. Over a handful of windows, PCW asks for input on all the typical parameters needed for flexo plate making and printing: plate exposure, processing system, plate type, press, substrate, ink, tape, anilox and print target. “Behind the scenes, the tool uses all critical print parameters and variables to automatically generate the perfect screens and curves for any application,” Marsoun says. “Unless someone intentionally overrides the settings, each plate will be created exactly the same.”
The screening algorithms PCW spits out are called Esko Crystal Screens. They make use of other Esko technologies including Pixel+, where each dot is made of individual pixels. Esko Crystal Screens implement a transition from solid dots in highlights to Pixel+ dots in the rest of the tonal range. Depending on a printer’s specific setup, the screens can also utilize FM screening in the highlights and support dots at single or double ruling.
The process of optimizing screening and curves, even for someone with a strong knowledge of flexo printing and prepress, is a time-consuming one: Print a test image with different screens and tone scales, analyze the target either visually, or with a spectrodensitometer—or both—to determine what appears to be the best highlight and solid screening option, then measure the tone scales and input them into curve-generation software.
“This process can easily take an hour or more,” Marsoun says. “In contrast, with PCW, we simply use an i1IO [scanning table] to automatically measure special test charts into the software and in a few moments, it recommends the best screening option. The user then has the option to validate the selection. Once confirmed, the software generates curves and screens.” He says that process, on average, will take no more than 10 minutes to 15 minutes.
With a Wave of the Wand…
There are two general groups to which PCW can appeal: printer/converters and prepress providers. Marsoun says the former will like the software’s ease of use, while the latter will appreciate the quality of Esko Crystal Screens.
Photo courtesy of Esko
Drilling down into specifics, he says PCW’s main benefits are a reduced implementation time for screens and curves (brought about by the wizard-based approach to generate them), quicker daily repro tasks (10 minutes to 15 minutes per color, due to plates staying cleaner, and five minutes to 10 minutes per file through the “dot cleanup” function that automates retouching), simplicity (allowing users to make plates without an expert’s aide, and allowing an expert to do things that do require an expert’s aide) and objectivity in decision making (taking the pressure off the human eye).
With Esko Crystal Screens, printers get consistent plates, stable dots, open highlights and shadow detail, along with on-press results that include limiting the “grainy effect” caused by stochastic dots, a reduction or outright removal of the “hard edge” common to flexo printing and a more robust highlight dot offering.
Marsoun singles out another result of those screens—press results that impact Overall Equipment Efficiency (OEE). Customers report plates coming up to color faster and needing fewer press stops to be cleaned. A 2 percent highlight that previously printed at 20 percent instead prints at 6 percent or 7 percent, while midtones show less dot bridging and print cleaner.
“The screening algorithm is unique because its focus is on the entire tonal range,” he explains. “For example, with flat top dots and dimpled shadow dots that are able to hold more ink, not as much pressure is needed on press. Dots just print cleaner.”
A result of cleaner dots and improved print quality could be customers that look to convert jobs to flexo from gravure. To do that, PCW is equipped with a feature that allows a plate maker to minimize graininess by controlling where the transition from AM to FM takes place. The software does this by suggesting the optimum transition point if there is a particular target (for example, an ISO curve), but also allows for individual adjustment to suit specific requirements; the operator can see the impact on tonal values in real time.
Seeing Is Believing
A not-uncommon workflow for a color expert might be to place a selection of screens on a plate and send them to a customer for testing, ultimately choosing the option that looks like it would work the best.
PCW and Crystal Screens enable a different workflow, one which is “innovative in terms of how we could prepare screens to test with our print customers,” according to a prepress provider who has used the software for the last year.
“Now, when we print a sample, it automatically reads the results of the test chart and imports a lot of information about the print variables—for example, the anilox, plate and tape,” the prepress provider’s president explains. “From there, the software recommends the preferable dots, screen and curves to use. That makes it much easier and more productive to set up a plate and to go through all the stages to the final print.”
That provider also calls attention to needing less pressure to get “great” density, being “amazed” and “surprised” at an absence of dirt in dots, “very” consistent colors verified by L*a*b* measurements and reaching for 200 lpi on flexible packaging after producing plates at 150 lpi and 175 lpi.
“The first job we ever prepared [with PCW] was for a line of SKUs for a six-pack of bottles printed on PE with high-quality graphics and lots of images and gradations. It was a complex job, and the printer and brand owner had very high expectations,” the company’s president recalls. “They were very pleased with the results and did not have to stop the press to clean the plates. Previously, the printer had to stop the press every 30,000-ft. or so. Now, they run all day.”
The Peacemaker
PCW is a tool that can take the knowledge and skills of color experts and make them available, on demand, to future generations of flexographers. In that way, it brings together two groups separated by decades of learning and working.
There are two other groups that Marsoun says can be brought together by his company’s software, groups separated only by the fingers they routinely point at each other.
“In every pressroom, there is always a press operator blaming prepress and in every prepress department, a prepress operator blaming the pressroom,” he observes. “There are some print defects that have always been solved by adjusting inks or impressions, that we are now learning can be eliminated by improved screening technology.” Take dirty print: Marsoun says it has as much to do with curves and screening as it does with how the operator sets up the press and manages the inks. PCW benefits both sides, providing prepress with worry-free and consistent results and allowing press operators to look elsewhere for trouble.
“Our goal is to continue to build more sophisticated and robust prepress and plate making solutions that are less sensitive on press, so operators can worry about things other than solving print defects caused by less-than-optimal prepress.”
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