VIGC, the Flemish Innovation Center for Graphic Communication, has run the rule over a raft of popular and lesser-known PDF viewing tools. The results are an eye opener for anyone involved in publishing or printing, as most tools do not display a PDF/X correctly. And iPad apps for viewing PDFs put in a poor performance, making them unreliable in a design or prepress environment.
"Using the right tools, with the right settings, is essential," says Eddy Hagen, Managing Director and trend watcher at VIGC. "In a design and prepress workflow you have to be sure that the tools you are using work correctly. A PDF that has been made according to best practice, and which complies with the PDF/X standards, should be shown in the correct format. Unfortunately, this is not the case with many tools. We have been aware of this issue for some time, and the test results bear out our concerns."
VIGC tested more than 20 tools, including Adobe® Acrobat® and Adobe® Reader®, as well as popular alternatives like Foxit Reader and Mac OS/X Preview. In addition to these desktop applications, some iPad apps and three online tools for PDF file sharing were also tested. An important part of the tests was test patches from the Ghent PDF Workgroup (GWG). Some of them were designed by VIGC, which is an active member of the GWG. These are perfect PDF/X files, but with specific yet quite common properties for printing.
"Not everyone is aware that a PDF viewer essentially does the same as a RIP,” explains Didier Haazen, PDF expert at VIGC. “It translates the information inside the PDF on a specific output device, in this case a screen. This is why our test is so important. If you use an inappropriate PDF viewer, you can’t be sure that what you see on your screen is what will come out of the RIP, out of a digital press. In our test, we have clearly seen that many developers didn't implement the complete 'PDF reference', which is more than 1300 pages thick."
No theoretical exercise – a real life print issue
VIGC decided to conduct the test following many questions over the last few years from the organization’s members: "The tests were not a theoretical exercise,” explains Haazen. "Only a few weeks ago we again encountered the problem where the customer asked the printer where the white text had gone. But the printer had never seen white text in the PDF, as the designer had put the white text in 'overprint' and white text in overprint is not visible – it should have been 'knocked out'. The designer used Mac OS/X Preview to check the PDFs, but that tool does not understand the overprinting concept, which caused it to display the white text."
Wrong tools pose liability risks
Using tools that do not support all properties of the PDF file format is certainly not without risk, according to Hagen: "Suppose a customer’s legal department has to approve a print-ready PDF but uses an imperfect PDF viewer or online PDF sharing tools. This could make some essential information visible to them, but cause it to 'disappear' at the printer because the white text was set to 'overprint'. This could have huge consequences, especially if it’s a leaflet for pharmaceutical products or a financial services prospectus.”
Use the right tools in a printing and publishing workflow
Hagen is unequivocal when it comes to using the right equipment: "We appreciate that many users of PDF readers might consider our tests irrelevant. Lots of tools we tested aren’t aimed at the printing industry, and there’s certainly a specific market for those tools. In the printing industry, however, we have to raise the bar. Incorrectly showing a PDF can lead to unnecessary costs, as jobs may need to be reprinted. This is why we advise designers, marketers, publishers, printers, ... to only use reliable PDF viewers in a printing and publishing workflow. Adobe Acrobat and the free Adobe Reader are good choices, however the other tools we assessed failed in many of our tests."
The test report, including an overview and the results per application, can be purchased at VIGC.