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Evolutions in food packaging printing

You are here: Conferences & Events * 2009 Stockholm * Abstracts * 3. Printing and print quality

3. Printing and print quality

3.01. Pressroom draw variation and its impact on web breaks Part II: Commercial pressroom trials

Nina Deng, Frédéric Parent, Tony Manfred, Joe Aspler, Jean Hamel

In the first report of this series, we characterized the draw variation of newsprint webs in a number of North American newspaper pressrooms using the technique of laser Doppler velocimetry. We showed that there is a good correlation between web break rates and pressroom draw variation. In this report, we have extended the draw variation study to commercial pressrooms, including heatset offset, coldset directory offset, and gravure printing. A wide range of draw variations was seen, likely related to the wide range of press operating and maintenance conditions. Also, as is the case with daily newspaper pressrooms, the contribution of paper is small. For a given draw variation, the web break rate in a heatset offset pressroom is significantly higher than that in newsprint pressrooms. This may be due to the fact that heatset offset presses are more complex. Case studies demonstrated that the draw variation can be reduced through improved press maintenance and operation.

Keywords: Runnability, Web Breaks, Tension, Offset printing, Gravure Printing
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3.02. How to utilise improved newsprint - balancing image quality and set-off

Marianne Klaman, Per-Åke Johansson, Erik Blohm

Contrary to standard newsprint, which is highly standardised when it comes to paper properties and the prepress and printing parameters, there is a lack of standards governing improved newsprint. If the prerequisites are not accurate, the quality can actually be worse than for standard newsprint, due, among other things, to set-off and smearing, which is the most evident problem with improved newsprint, related to print quality. One occurring problem is also that the images are too dark and, as a result, there is a loss of detail. In the investigation presented here, the necessary actions to ensure optimal print quality and the lowest possible level of set-off were considered. Paper samples were printed with different levels of print density and total ink coverage area (TIC). The printing trials were conducted at three newspaper printing houses. If certain measures are taken, it was shown that improved newsprint has the potential of resulting in improved image quality, due to a larger colour gamut and a higher relative contrast, when compared with standard newsprint. An ICC Profile, well adapted to the conditions in different printing presses and paper qualities and careful adaptation with regard to crucial parameters, such as the total ink coverage area and K value, is helpful for achieving a high quality image, together with a minimised risk for set-off.

Keywords: Improved newsprint, Adapted ICC profiles, Set-off, Print density, Image quality
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3.03. Printing by the numbers on commercial paper grades

Petter Kolseth, Luc Lanat, Örjan Sävborg

Printing standards have been around for many decades, but the detailed ISO standardisation evolved only a little more than ten years ago. The graphic standard series ISO 12647 Graphic technology - Process control for the production of halftone colour separations, proof and production prints is making an ever stronger impact on the graphic industry. This has, unfortunately, created unnecessary confusion. Especially there are some details in Part 2: Offset lithographic processes that sometimes result in a clash between supplier, printer and print buyer. The limitation to a few specifi c paper types with characteristics that hardly match commercial paper grades, and the not always realistic targets for printed colour and tonal transfer giving rise to sometimes endless debate. The present work describes some of the measures that have been taken by us as a paper supplier to alleviate the situation. As a general conclusion, we may state that a majority of commercially available papers could be confi ned in rather narrow groups with respect to shade, attainable printed colour and tone value increase, provided that the right parameters are chosen.

Keywords: Color management; Lithographic offset; Paper characterisation; Paper optics
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