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FLEXO Magazine : June 2012
FTA TODAY Forum Flashback FQC’s Unanswered Questions The 2012 Forum was jampacked with speakers, presen- tations and questions from all across the flexographic field. With only so much time to cover a wealth of information, a few questions went unanswered—until now. Thanks to the chairs of the Flexo Quality Consortium (FQC), and others, this FLEXO exclusive will examine a number of unrequited questions. Steve Smiley, Vertis Communications, delivered a stan- dards update concerning ISO activity that will impact the flexo industry. The presentation simplified the lengthy stan- dards into content that can be easily understood and com- municated to manufacturers allowing appropriate action. Below he responds to a pressing question concerning D50. FLEXO: Why is the new D50 still called D50 rather than some sort of modifier to make the semantics less difficult? Like D50a or D50-2? Smiley: D50 is a theoretical light with even illumination that is close to the color temperature of daylight. D50 did not change. Only the viewing requirement changed. P.J . Fronczkiewicz hosted a detailed look into platemaking negligence with his presentation: “Ever Wonder What Would Happen If...” T he demonstration explored plates made using the latest technologies (flat top dots, surface screening and high definition) with known processing errors and put these new tools through extensive testing. Below he answers a few questions that were not touched on during the show. FLEXO: What is the effect, if any, of flat top exposure versus round top exposure on solids? In other words, “ with and without oxygen.” Fronczkiewicz: With oxygen-inhibited exposure, or round top, the top surface layer of the plate (~0 .001 inch) is never cross- linked and is washed away during processing. Unless surface screening is applied during prepress, the plate will have an inherently smooth surface. But, even then, round top plates are limited to relatively coarse surface screening patterns. This is due to the role that oxygen plays during exposure. Plates exposed without the influence of oxygen (flat top)— by means of a barrier layer or acceleration—will also have similar smooth surfaces without the benefit of surface screen- ing. However, the patterns that can be rendered into the surface via prepress can be much finer. This occurs because oxygen does not prevent the surface layer from forming. One drawback is that unwanted residual laser lines and debris might also be held in the plate surface with greater fidelity and can create visual print defects. In short, without the use of surface screening, there is neg- ligible difference between the surfaces of round top and flat top plate types. Flat top technology greatly expands the range of surface screening patterns that can be held. But, there is some risk of holding unintentional structures if present during main exposure. FLEXO: In your tests, did you find that 65,000 impressions were enough to determine a long run? Most converters look for more than one million feet of impression. Fronczkiewicz: As an “elimination round” with many variables and a limited testing timeframe, 65,000 impressions was enough to make some generalities. We were able to discover the effects of plate processing, properties, and technology on printability and—to a lesser degree— wear. Our focus can turn toward longer wear tests by eliminating the variables that had no obvious effect. I would certainly agree that it is dangerous to make long run predictions based on this test. But, the conclusions drawn were intentionally cautious. This question shows the great benefit of the FTA Forum: great questions and critique of work presented. This ultimately leads to more pertinent projects that are beneficial to all. Paul Lancelle, Eastman Kodak Co., offered up a detailed discussion titled, “Do More With Four,” which examined the utilization of process print to extend the capabilities of the flexographic color gamut. Lancelle demonstrated the use of current technologies proven to extend the color gamut of flexo. The presentation included case studies that demon- strate the capabilities of four-color process in flexo compared directly to ECG technologies. Below, Lancelle will respond to a number of questions that went unanswered at the Forum. FLEXO: You have proven that enhanced surface expands the CMYK gamut by a large amount. Why not combine enhanced surface with 7C (extended gamut) to get an even bigger gamut? Lancelle: For those printers who are committed to (and successful) with the expanded color gamut (ECG) process, it would be interesting to discover the potential gamut capabilities achievable by combining the two technologies. FLEXO: Do you suggest that we NOT use the FIRST color standards? Lancelle: It is important to remember that the current FIRST solid ink density specifications were established prior to the introduction of some of the more advanced technologies available in the market today. I would recommend establishing “minimum-maximum” ranges of density specifications, with the current FIRST density targets established as the minimum. 18 FLEXO jUne 2012 www.flexography.org