Big print publishers use this PDF standard for high-resolution output. You should use it if you need to send your PDFs to a publisher or printer, or simply want excellent quality printing results.PDF/X: the acronym might sound like a secret government program or a stain remover, but it's actually a restricted subset of Adobe's PDF specification created for high-resolution print output and file exchange.
The PDF standard helps print publishers save money by preventing costly prepress mistakes.
A garden variety PDF, created by any number of PDF writers, can include features that don't reproduce well on a high-resolution printing press. PDF/X restricts those elements—Java Actions, annotations, audio, attached multimedia files, hyperlinks and more—from being included.
Developed by the Committee for Graphic Arts Technologies Standards (CGATS), the PDF/X standard also eliminates a number of the most common prepress errors, including missing fonts, missing images and incorrect color space.
Martin Bailey, senior technical consultant at Global Graphics and vice-chairman of CGATS, wrote in an e-mail interview that PDF/X moves publishers "closer towards ensuring that a file will be printable."
Use Tiger's Automator to streamline your PDF workflow. Click here to read more.
However, wrote Bailey, "There's a widespread belief that PDF/X is supposed to ensure that files will print perfectly, but that's not really true, partly because it probably isn't possible to do that. What the standards do is to greatly reduce the possibility of errors, when reasonably modern prepress equipment is used."
While not all desktop print publishers use or even know about PDF/X, many large magazines have been using the file format for years. Time Inc.'s 56 magazine titles reportedly account for about 25 percent of all magazine ads, and the company mandated in 2002 that all their advertisements be submitted as PDF/X files and announced they would send only PDF/X files to their printers.
Three Flavors of PDF/X
There are three basic PDF/X flavors, and two more are being created.
PDF/X-1a is the most widely used standard in North America today. Publishers considering sending their printers PDF/X files will most likely send this type. Time Magazine mandated the use of PDF/X-1a for digital file submission and sends their printers all their magazines as PDF/X-1a files.
Of the three current flavors, PDF/X-1a is the most restrictive, requiring all fonts and images be embedded and all elements to be encoded as CMYK (cyan, magenta, yellow and black) or spot. Despite these restrictions, as Bailey noted, PDF/X can't solve all prepress issues (such as incorrect bleeds, folds and page size issues).
PDF/X-2 was created for OPI-like workflows and doesn't require images to be embedded. It is a specialized variety of PDF/X that may work best for high-volume publishers interested in keeping their images separate from their PDF files.
PDF/X-3, which is seen by many as the eventual successor to PDF/X-1a, was developed to take advantage of color-managed workflows and allows the use of device independent color spaces. PDF/X-1a can only handle CMYK and not color-managed data.
PDF/X-3 was largely developed by European graphic arts groups. Publishers who print in Europe or graphic artists making advertisements for European magazines are more likely to use the format.
Content creators outputting to digital presses should consider submitting PDF/X-3 files to their printers as well as publishers who are sending the same file to different printers and different presses (offset litho, gravure, flexo or toner).
There are three basic types of PDF security. Click here to read more.
Cross-media publishers (Web, digital, PDF, print) can reap savings by keeping their images in the RGB color space instead of converting to CMYK just for print and submitting color-managed PDF/X-3 files. However, there are a number of hurdles to jump over before considering that option—including if the printer has an output device that supports in-RIP separations.
"The color-management in PDF/X-3 brings in more workflow issues than PDF/X-1a," said Bailey in an e-mail interview. "And many vendors still have to iron out some issues with handling those, especially in environments where many files from diverse sources are merged together, such as in magazine advertising."
PDF/X-1a, PDF/X-2 and PDF/X-3 were recently updated for 2004 versions, which means the standards are compatible with Acrobat 5+ and PDF 1.4. (The Portable Document Format has its own versioning system.)
"The PDF/X committee is hard at work on PDF/X-4 and PDF/X-5 to address newer features of PDF such as transparency and layers," said Leonard Rosenthol, chief technical officer at PDF Sages Inc. and a CGATS SC6 Task Force 1 (PDF/X) member, in an e-mail interview.
Document Management 
