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Prepress Developments



The hardware and software required to turn an image into a press-ready plate continues to advance as technology reaches far into digital realms.



Published January 15, 2010
Related Searches: Flexography Flexible packaging Platemaking Flexo plates
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Prepress Developments



Forthcoming software from EskoArtwork will allow prepress personnel to design and view shrink labels on screen.

The hardware and software required to turn an image into a press-ready plate continues to advance as technology reaches far into digital realms.



By Jack Kenny



The sole purpose of prepress, in flexography and other print processes, is to convert an image into a printing plate. That simple goal requires skill, intelligence and the proper tools. More and more, it means that the prepress specialist has to have an understanding of color and its scientific parameters, of the complexities of the print process, and the challenging nature of the printing plate. Prepress has evolved from the old camera and film days to a digitally controlled process that brings forth amazingly crisp and powerful images. Many are those who still produce plates using conventional plate washing systems, but the digital imaging and processing format that began to emerge a dozen or more years ago has taken hold and has changed the prepress landscape forever.

The move away from film to digital flexo plate imagers was a major change in the imaging process. It allows digital images to be delivered to the surface of the photopolymer plate with great accuracy and repeatability. Several imaging equipment manufacturers made the move to adapt their film imagesetter technology to address the characteristics of a carbon mask surface on the plate. This required higher output lasers than those typically used to expose light sensitive film. The process involves ablation of a mask that has thickness, and production of an image that has smooth and crisp edges ready for UV exposure. This technology is similar among all manufacturers, but the delivery system — how the image is digitally transferred to the plate surface — is handled differently from one to the next.

The comment most heard from those who have adopted the digital platemaking systems is consistency. While quality might be argued still, there’s no debate about the consistency of the plates, time after time. Over the years, those who had panned the new process have dwindled in number, having seen the results of comparative trial after trial, many times in their own environments.
Prepress will continue to pursue technologies that render packaging products ever more pure and pleasing to customer and consumer alike. Here are a few.

DuPont Packaging Graphics


Late in 2009, DuPont Packaging Graphics announced the development of the Cyrel XD Hybrid Digital Plate System. DuPont holds many firsts in the flexographic industry, including the development of the first photopolymer plate. In the late 1990s the company unveiled a new system for plate processing, a dry thermal system called FAST, which has become extremely popular in the narrow web industry.

The new XD Hybrid Digital Plate system allows flexographic platemakers to produce a hybrid digital dot using their existing digital workflows. The resulting hybrid digital dot has a flat top, the company says, and broad supports similar to those produced in an analog workflow.

Ray Bodwell, marketing manager for DuPont Packaging Graphics, says, “The Cyrel XD system will allow digital platemakers to use their existing computer to plate (CTP) and plate making systems to produce the hybrid digital dot on an ‘as-needed’ basis. A low-cost modification to the UV main exposure unit will allow the flexographer to turn the Cyrel XD system on when they wish to produce a hybrid digital dot, or off when they wish to produce a traditional digital dot.

“The commercialization of digital Cyrel in the mid-1990s introduced the digital dot and ushered in an era of improved consistency, productivity and quality in flexography,” he adds.

“However, we recently found an exception in the corrugated segment, where a more traditional flat-topped dot with a broad base helped to minimize the appearance of fluting. In 2008, we introduced DigiCorr as the solution. While testing has shown that the conventional digital dot profile still produces the best image carrier for most flexo applications, in those cases when a customer needs the digital hybrid shape, Cyrel XD systems will allow them to do that.

“During these challenging economic times, DuPont Packaging Graphics intends to bring solutions to our customers that help them maintain their competitive advantage without having to recapitalize,” says Bodwell. “Systems and upgrades need to be low cost, and workflows need to remain flexible and open. The DuPont Cyrel XD system is low-cost, and there are no proprietary films or consumables associated. In the end, a customer can just drop it in and go.”

EskoArtwork


Formed in the recent past by the merger of two former rivals – Esko Graphics and Artwork Systems – EskoArtwork is one of the companies at the forefront of prepress technologies, both in hardware and software. The company’s CDI Spark digital laser imager is as widely popular as DuPont’s FAST system, and quite often are found in the same platemaking rooms at converting companies.

EskoArtwork continues to explore new avenues in its quest for prepress excellence, and has recently developed a system that it calls HD Flexo, aimed at the creation of the smooth and disappearing vignette. Ian Hole, the vice president for market development, provides details:

“For the last 12 years, 99.9 percent of digital flexo worldwide has been using resolutions for files that get imaged between 2,400 and 2,540, regardless of imagers,” Hole says. “However, EskoArtwork saw that over the last two to three years, the demands of people in the printing industry, especially in labels and flexible packaging, have been looking for better quality images. Not that the available equipment is bad, but they wanted a higher level because everyone always wants to outdo others on the shelf with packaging. Shelf impact is a big driver here. Big corporations would have conversations with converters about improving their packaging, and anything the converter could offer would be a good thing.


An example of EskoArtwork’s HD Flexo
“So we realized, about two and a half years ago, what we might have to develop. Since the beginning of digital imaging – almost – we have had the ability to raise the resolution from 2,540 to 4,000, to 8,000, even to 10,000.” These high resolutions are being used today, he adds, for printing of bank notes, stocks, bonds, lottery tickets, and other security items.

“To accomplish this means changing the lens cylinder in the optical system, bringing the spot size from 12 to 13 microns down to 8 microns. Every image on the plate is going to be a little smaller; everytime you describe a graphic file, dot, line, piece of text, anything, in a much finer way, the quality of that description is higher. By raising the resolution of the imaging file to 4,000 you are increasing the number of pixels in any file three times. In theory and in practice, every pixel is a third of the size of the original pixel.

“The second part of this is software. The challenge is to meet the demands for quality in flexible packaging and labels. Here we encounter the Achilles heel of flexo in general: When you take the gradation down to 3, 2 and 0 percent, you end up with a line where the printing stops. A press might be capable of printing down to 2 percent, but typically there is a hard line end in flexo. In labels and flexible packaging the requirements are much higher – itshould fade away down to zero, smoothly all the way down to white paper or clear film.

“We looked at all the screening technologies we have, inherited from Artwork Systems. We looked at the best attributes of many of our screens, the pros and cons. We then rewrote a new screen algorithm for HD Flexo. The choice was made that screens would be on a grid. Why is that important? Screens not on a grid are stochastic; there may be quite large gaps between one dot and the next. When dots are isolated, they tend to have the capability of acting like a loose cannon; the dot might bend slightly, so you print slightly on the side of the dot. That ends up printing a bigger dot than you would have had if you had just printed the top of the dot.

“Second, we wanted dots that could come all the way down to zero, whatever the plate type was. Instead of taking them down in a full range, we decided to make a salt and pepper look about this, because there was another advantage. Part of the algorithm is that it deliberately delivers dots of different sizes in a small area. The dot size might average 4 percent in a given area, but some are slightly bigger and slightly smaller than 4 percent. Take that down smaller, some over 2 percent, some 1, some one-half percent. Or not measuring at all. If you logically take that down, the salt and pepper effect is good for the human eye. They selectively, gradually fade away. As they fail to print because they are so small, not formed well enough to take ink, they default to the dot next to them. They support the other dots, keeping them upright to do the job.”

In tests conducted in early 2009, Hole says, printers could carry on printing these plates as though they were normal digital plates. There was no change to anilox sizes, impression levels, or ink levels – maybe just minor, everyday changes.”

HD Flexo is an upgrade that can be added to all CDIs or EskoArtwork imagers, except those from 1997-98. “People are trading in these devices. The upgrade, Hole notes, is approaching US$50,000. It includes hardware, software, installation, service, and calibration to presses and all printing attributes.

Visualizing labels and shrink


EskoArtwork has also been at work on the design side to improve its Studio software, a family of tools that deal with 3D in packaging. The company has such a visualizer for boxes, and now, in this quarter, the launch of a 3D tool for labels and shrink sleeves will hit the market.

“The next upgrade will bring us to Suite 10, and it’s now confirmed that by the end of March we will have that ready for volume distribution,” says Jan DeRoeck, director of solutions management for EskoArtwork. “That is all encompassing software, with upgrades for all our components, including the Studio family.

“Studio relies on a designer window, a preview window that uses CAD information to display what you are designing in 3D. It needs CAD information to create structural design. For a label, the idea is that a customer can input or create the bottles himself. If it’s a simple circular kind of bottle, there’s an easy-to-use toolkit to draw the contour, and use that shape to start visualizing label designs. If it’s a more complicated bottle design, then the toolkit has the capability to import the collada file format. With that format it’s possible for a label designer to contact the bottle designer and get actual CAD data for the bottle, then work on the label.”

In the store at EskoArtwork’s website, one supplier of plastic bottles has made available 15 shapes from collada files for users to work with. “The value proposition is very clear,” says DeRoeck. “There is a much tighter relationship between the container manufacturer and the designer.”

The 3D shrink application is a stand-alone app for a Macintosh, DeRoeck says. “The toolkit for shrink is a CAD application to design structures for shrink sleeves. Using acollada file format you import the container design, even a six-pack of metal cans. Using the interface, you can draw a sleeve around the container. The software will emulate what happens to the substrate in a shrink tunnel. The design can be imported into Adobe Illustrator.” EskoArtwork has been busy working with substrate designers so that all major substrate details are input into the program.

Kodak


Kodak, ever committed to innovation in package printing, has introduced a new addition to the Kodak Flexcel NX Digital Flexographic System that enables smoother and more consistent transfer of ink on press. The application of new Kodak Digicap NX screening to the entire image area allows printers to produce Kodak Flexcel NX digital flexographic plates that can improve print quality throughout the full tonal range and expand the achievable color gamut.

“Plate users can now enjoy stronger colors and outstanding visual appearance in solid areas, in addition to the fine highlight detail and print consistency delivered by the Flexcel NX system,” says Emma Schlotthauer, global marketing manager for flexo plates.

This new feature, she says, applied in the Kodak Tiff Front End Software, “utilizes the high resolution capabilities of Kodak Squarespot imaging technology and the 1:1 reproduction capabilities of the Flexcel NX system to create micro-texturization of the printing surface. The resulting improvements in ink transfer deliver enhanced print quality and production efficiencies. This allows flexo platemakers to more easily mix areas of solids and halftones on the same plate.” The new feature also helps to reduce setup time on press with plates that come to color more quickly, she adds.

“Extensive trials in the flexible packaging market have yielded excellent results,” says Schlotthauer. “Customers have been delighted with the gravure-like appearance of the solid areas and amazed that they can now enjoy higher ink densities while still maintaining the finest highlight detail.”

Kodak has been recognized by the flexographic industry for its technical innovation. The Flexcel NX system was named last year as the recipient of the 2009 Flexographic Technical Association Technical Innovation Award. It also received the 2008 PIA/GATF InterTech Technology Award and the Flexographic Pre-Press Platemakers Association Technology Innovator of the Year Award.

“The beauty of this new development is that it builds upon the core benefits of the 1:1 image reproduction and flat top dot structure that characterize the Kodak Flexcel NX system,” notes Schlotthauer. “Users of the new feature are reporting plate, ink and substrate savings, with printed results that are impressing clients and helping to drive new business.”



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