For Position Only: The PDF/X Files

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As if adopting a PDF workflow weren't enough to keep you busy, you've probably heard at least murmurs of something called PDF/X. Or rather, PDF/X-1, PDF/X-1a, PDF/X-3...STOP!

I hear you. You don't have to shout. I know it's daunting, but rather than cover your ears and yell at me, why don't you let me tell you what PDF/X is, and why you should care. That's what I'm here for.

Back to Basics
Let's start with the basics: PDF, the cross-platform file format typically created with Adobe Acrobat Distiller (which these days is part of Adobe Acrobat), is rapidly becoming the norm for file transfer in the prepress world. When properly created, PDF files are compact, complete, and composite, allowing prepress professionals to take your page-layout designs and efficiently prepare them for printing -- namely, trap, impose, and separate them. The reason prepress folks and printers like PDF is that it's reliable. They can perform such tasks with confidence that the job will print as intended.

The problem is that PDF can be used in many more ways than just for prepress. They can include comments and annotations, for example, and they may be made with RGB colors, or perhaps without embedded fonts. When a prepress provider opens a PDF file with any or all of these conditions, that slows down the production process.

PDF/X, which is a derivative of the full-fledged PDF format, was created to make PDF in the prepress world reliable and dependable -- to facilitate "blind exchange," as its authors like to say. But I'm getting ahead of myself.

The Rise of PDF/X-1
The PDF/X standard was developed by the American National Standards Institute's (ANSI) Committee for Graphic Arts Technologies Standards (CGATS) at the request of newspaper publishers and advertisers. These folks wanted a standard for exchanging vector advertising data like that of the raster TIFF/IT format. What CGATS (pronounced "see-gats") came up with was PDF/X-1, which is basically a PDF file with certain things disallowed: RGB images, annotations, form fields, and comments or other objects that might get in the way of making separations or might compromise final output quality.

By restricting what is allowed in a PDF file, the PDF/X-1 standard lets advertisers and publishers, and others with a relatively closed workflow, streamline their production and feel more confident of the quality of the file being printed. This is what's meant by "blind exchange," and these folks are the market for PDF/X-1. By making sure its files comply with the PDF/X-1 standard, an agency can quickly and fluidly send out a single file to multiple publication printers, knowing that they've provided a CMYK file that will print as expected.

For those of you who are gluttons for punishment, I'll briefly go a step deeper into PDF/X-1 (the rest of you can skip to the next paragraph): There are actually three versions of PDF/X-1. First is PDF/X-1:1999, which was approved in that year and is based on the old PDF 1.2 spec, which means it can't handle duotones; a more current version, PDF/X-1:2001 is based on the more robust PDF 1.3 spec. Otherwise, these two versions are the same. A third, slightly narrower version, PDF/X-1a:2001, prohibits OPI and file encryption.

Other PDF/X Flavors
Now, recognizing that not all print production workflows are alike and that not all file transfer is "blind," the standards folks didn't stop with PDF/X-1. Commercial and packaging prepress production and printing is an entirely different can of worms from advertising for publications -- a can that basically sits open on the counter, where anyone can help themselves to the file -- so the CGATS standards folks created another, open version of PDF/X for this type of printing. This one is PDF/X-2.

PDF/X-2, which is still working its way through the standards committee, is a more flexible format than PDF/X-1. For example, it's not limited to CMYK. It supports the LAB color space and ICC color management as well as OPI workflows, and it does not require that fonts be embedded. And since it was developed more recently, it's actually based on the most current PDF spec, 1.4, which supports transparency. Because PDF/X-2 is more flexible and open than PDF/X-1, it requires good communication between designer and vendors to make sure problems don't arise (for example, that the prepress provider has copies of all fonts that are not embedded in the file), but it still offers a solid foundation that ensures designers initially provide good, clean PDF files to their print partners.

There's one more PDF/X standard floating around out there that you should know about: PDF/X-3. I'm explaining these standards to you in numerical order, but X-3 is actually more closely related to X-1 than X-2. PDF/X-3 is for the same market -- print publication advertising -- but unlike PDF/X-1, PDF/X-3 files aren't restricted to CMYK and spot colors. This standard supports LAB color and ICC color profiles. In other words, X-3 is for color-managed workflows (and it's based on PDF 1.3).

Which Is Right For You?
Let's see a show of hands: How many of you skipped from the intro down to this subhead? Don't worry, I don't take it personally. Here's the long and short of it:

  • If you do ad delivery and/or catalog work in the US, use PDF/X-1a. If you do ad delivery or catalog work in Europe, use PDF/X-1a or PDF/X-3.
  • If you're in commercial or packaging printing, use PDF/X-2 wherever you live.
  • If your jobs are destined for digital presses (which aren't addressed by SWOP and SNAP standards), use PDF/X-3.

A more relevant question for some of you might be "Is PDF/X right for me at all?" That I can't answer. If you're successfully providing your prepress partners with PDF files that they process with no problem, then probably, no, you don't need it. But PDF/X might become useful if, for example, you upgrade or change your design applications, or start working with new print partners who aren't up to speed on PDF. If you think PDF/X might make your production process more efficient, talk to your prepress partners. Those in the know about PDF/X can help you configure Distiller and use other assorted applications, such as those from Apago and Enfocus to convert or preflight PDF files so that they comply with the standard. For a complete list of PDF/X tools, go to the Digital Distribution of Advertising for Publishers Web site. More information can also be found at this PDF/X info site.

Read more by Anita Dennis.

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