The title of this article may have confused you. Isn’t PDF perfectly suited for graphic arts? Wasn’t the format developed for print and publishing? Then what can be so terribly wrong with my files?
Actually, PDF was not developed for use in graphic arts. It was developed as a format for the Internet and enterprise world, and until the third revision of the language, it was generally unusable for graphic arts production. The file format has evolved, of course, and the later versions of PDF (starting with PDF specification version 1.3) are perfectly suitable for a wide spectrum of graphic arts applications.
That inheritance caused a lot of non-graphic arts features to be built into the PDF file format. It makes PDF so versatile, but it also presents a danger for graphic arts workflows. For example, what happens when you include a sound fragment or a movie in a file that is going to be printed? There are plenty of opportunities to create a PDF file that will not print correctly or not print as expected. Let’s look at some of them.
Different PDF Versions
The original PDF version was (logically) 1.0. Right now we’re up to version 1.6. That poses a problem, as not all software and hardware can handle the latest versions of PDF documents. Being able to have transparent objects in a modern PDF file is a cool feature, but not all RIPs know what to do with such a file.
Colors
The large majority of graphic arts workflows are based on CMYK and spot (named) colors. PDF files allow for much more than that; they support RGB, LAB and different types of color managed colors. Sending such colors to a press might result in the press giving up and printing nothing, or in hideously incorrect colors being printed without further warning.
Images
PDF files support images in any resolution. Low-resolution images might look acceptable on screen, but when printed, they’re a lot less impressive.
Fonts
PDF is very versatile with regards to fonts; from the beginning, the format was designed to alleviate font problems by supporting font embedding. If a font is embedded, the designer doesn’t have to send it with the document. All information needed to display that font is present in the PDF file itself. Unfortunately, a font does not have to be embedded when the PDF file is created. If it is not embedded, Adobe Acrobat will fake it on screen, but a printer will either not print the file or print it incorrectly (substituting the missing font with Courier, for example).
A number of these problems aren’t visible when you preview the file with Adobe Acrobat Reader. Only specialized preflight tools can pinpoint those problems so they don’t slip through.
These problems don’t mean that PDF is a bad format for graphic arts use. It does mean that proper care must be taken to create PDF files correctly and that you shouldn’t assume every PDF file is automatically good for print.
Editor’s note: For specifics on preflighting PDF files, see other creativepro.com articles:
David van Driessche has served as CEO of Enfocus Software, which produces PDF preflight software, since March 2003.
This article was last modified on September 16, 2005
This article was first published on September 16, 2005
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