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Ghent Workgroup tests large format digital specifications 

The Ghent Workgroup (GWG), a global body of Industry associations, suppliers and educators, has begun a public beta test of its new preflight specification that is aimed at improving quality control for sign and display printers.


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       David van Driessche, GWD

“The Sign & Display market segment covers everything from banners, over car wraps to billboards,” says David van Driessche, executive director of the GWG and chief technology officer at Four Pees. “Each of these products has their own technical requirements and capturing all of them in one specification was no easy task. After some research, it became clear we would have to introduce two key variables – viewing distance and scaling factor – to derive one specification.”

Viewing distance and scaling factor

Viewing distance is the average distance between the final printed work and a typical viewer. This can be as little as 1 metre (3ft) for banners, or as much as 75 metres (250ft) for highway billboards. This concept is used because typically, the bigger the viewing distance, the lower image resolution can be.

Scaling factor is another widely-used concept in the sign & display market. Because files can become very large, and typical editor applications are not always up to the task, many designers create their PDF file at half, 1/10th or even 1/48th of the final printed size. The rules in the Ghent Workgroup specification of course have to take this into account as well.

One specification to rule them all

“We could have created different specifications for each product type in sign & display, but that would have been very complex to create and maintain,” says van Driessche: “Instead, we incorporated the concepts of viewing distance and scaling factor and end up with one set of rules for the whole market segment. Of course, applications that create or preflight PDF files can choose how they decide to integrate the rules and could still provide different templates or preflight profiles for different product types.”

Wide gamut

The other factor that sets apart this new specification from earlier Ghent Workgroup specifications, is that it opens up which colour spaces can be used in a PDF file. This is important because of the number of wide-gamut output devices in use in this market. For the first time, a GWG specification allows the use of colour spaces such as calibrated RGB or L*a*b* for all elements within a PDF document.



The specification and associated preflight profiles are available from the Ghent Workgroup website now and can be downloaded from the new Sign & Display section on the GWG website.

This area also contains contact information in case you want to give feedback on the specification or preflight profiles, and a link to a webinar recording about this new specification given earlier by David van Driessche and Elli Cloots (Vice-Chair at the Ghent Workgroup and Senior Product Marketing Manager at EFI). Everything is available for free.

About Ghent Workgroup

The Ghent Workgroup, formed in June 2002, is an international assembly of Industry associations, suppliers, educators and industry members from around the globe. The Ghent Workgroup’s objective is to establish and disseminate process specifications for best practices in graphic arts workflows.

Since its inception more than fifteen years ago, the organization has produced numerous process specifications for PDF exchange, as well as developing useful tools for automating processes and testing and establishing consistent PDFs for print and publishing – all available free at www.gwg.org

Members are comprised of graphic arts associations including CIP4 (Switzerland), CMBO (the Netherlands), Febelgra (Belgium), Fespa (UK), Medibel+ (Belgium), PDFX-ready (Switzerland), Printing Industries of America (USA), and VIGC (Belgium). Vendor members include Adobe, Agfa, callas software, CHILI publish, Dalim Software, EFI, Enfocus, EngView Systems, Esko, GMG, Heidelberg, Hybrid Software, Kodak, Océ, Ricoh, Quark, Ultimate Technographics and Xerox IMPIKA. Industry members are agileStreams, JP/Politikenhus, Litografia Rosés, PB-Consult, Pragmeta, RRD and Sagamgraphic. Educational members are Ryerson University, the University of Wuppertal, Media University Stuttgart, the University of Ljubljana and the University of Novi Sad.