The Ghent Workgroup (GWG, Belgium) has released a new specification to address issues within the sign and display printing market – specifically viewing distance, scaling factor and support for wide-gamut colours. Viewing distance is the average distance between the final printed work and a typical viewer. This can be as little as one metre (3 feet) for banners, or as much as 75 metres (250 feet) for 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 large-format printing. Because files can become very large, and typical editor applications are not always up to the task of handling these, many designers must create their PDF files at half, 1/10th or even 1/48th of the final printed size. The rules in the Ghent Workgroup specification have taken this into account as well.
The other factor that sets apart this new specification from earlier ones, 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 currently used 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 the application settings built from it are available free of charge from the Ghent Workgroup website’s Sign & Display Corner: https://www.gwg.org/sign_display/.