THE LITTLE FORMAT THAT COULD
When it was first introduced in 1993, Adobe Acrobat was intended to provide a method for rendering documents in a form that could be read by anyone on any platform supported by Acrobat or the free Reader. (Trivia nugget: Reader was not originally free.) The primary purpose of the Portable Document Format (PDF) has always been to faithfully represent the text, graphics and layout of the original file, regardless of the originating application. This alone was nifty—obviously, file fidelity is important for office documents, both from a business and a legal standpoint. But we in the graphic arts looked across the hall and thought, “Hmmm … wouldn’t that make a great graphics format?”

GENERAL GUIDELINES
As long as we’ve been making PDFs, you’d think we’d have it down by now. Believe it or not, it is still possible to make a PDF that’s not perfect. Maintaining fidelity to the fonts and graphics used in the original application doesn’t sound that challenging, but the PDF must be appropriate for its destination, whether that’s web or print. So, how do you know what’s appropriate?

PDF files for print are “carriers” for your job. Image content must be of sufficient resolution (usually 300 ppi). Colors must be appropriately specified as CMYK, color-managed RGB or spot color. Fonts must be properly embedded. Any special requirements of the print-service provider—such as maximum ink limit—must be met. And you should think of such a PDF as a final job file: Don’t rely on editing as a crutch to fix a defective file. Go back to the original application, fix the problem and regenerate the PDF.

PDFs for e-mail or online usage must be small enough for a civilized download, so you have to strike a compromise between image quality and file size. Since pixels are the primary component in PDF heft, image compression is the best remedy for an overweight PDF. Text and vector graphics don’t constitute much of a PDF’s size, and they’re always crisp anyway.

If you’re posting important files such as product brochures or instructional materials on the web, you will have to fine-tune the file size/image-quality equation, juggling image fidelity against the need for petite PDFs. One solution is to break large files into smaller logical pieces, such as defined chapters or sections devoted to individual products, and then provide hyperlinks to the constituent files. That way, each individual file can be a bit larger without subjecting the end user to one gigantic download.

PDF FOR PRINT: BUILDING A BULLETPROOF PDF
When you’re asked to submit PDFs for print, your print provider should provide specifications for you to follow. But too many designers tell me that their printers simply say, “Just send us a PDF,” with no instructions for PDF creation. Assuming your content is healthy, how hard could it be to make a bulletproof PDF?

Does design software provide any clues? Let’s see: InDesign offers Smallest File Size, High Quality Print, Press Quality, PDF/X-1a:2001. … Clearly “Smallest” won’t be adequate for print, but “High Quality” and “Press Quality” sound good—and what about those weird X-flavored options? Turns out that “High Quality” is meant for desktop/in-house printing devices, such as that big color printer over there in the corner. “Press Quality” sounds perfect, but it allows live transparency, which may not be correctly handled by some older devices. So neither canned option is bulletproof for commercial print. Yikes! Your job is much too important for guesswork, so some guidance is in order.

The Committee for Graphic Arts Technologies Standards (CGATS)—which develops standards for the U.S. printing, publishing and converting industries—has supported and defined standards for PDFs for many years. As software and printing processes evolve, PDF standards have grown accordingly. That’s why you see the alphabet soup in the export options for Adobe InDesign and QuarkXPress: PDF/X-1a, PDF/X-3, PDF/X-4. … The “X” stands for “eXchange,” and these standards are meant to provide a platform for creating PDFs that can be exchanged between users with predictable results.

PDF/X-1a allows CMYK, grayscale and spotcolor images (e.g., duotones), but no RGB. Fonts must be subset, and the trim and bleed areas must be defined within the file. The PDF is compatible with Acrobat 4.0, which requires that transparency be flattened (yes, it seems old-fashioned, but that’s to ensure happiness with older processes and devices).

PDF/X-3 is for use in a color-managed workflow. RGB content is allowed, and color profiles are maintained. X-3 is also compatible with Acrobat 4.0. Sense a trend?

PDF/X-4 is a sign of the evolving capabilities (and needs) in the industry. This format allows RGB (with color profiles) as well as CMYK content, and is compatible with Acrobat 5.0, which allows live, unflattened transparency. If you’ve ever dropped a shadow in InDesign or QuarkXPress 7.0, this may seem much more enlightened. But many print shops aren’t quite ready for this more modern format yet.

If your printer doesn’t provide the correct option, how do you choose from the PDF X-files? Finally, some good news: You can’t go wrong with PDF/X-1a. Start with the PDF/X-1a option in InDesign or QuarkXPress, change one little setting, and you’ve made a bulletproof PDF. While the PDF/X specification insists on trim and bleed being defined in the PDF, it’s up to you to make sure that adequate bleed is included. While QuarkXPress 7.0 automatically includes bleed in a PDF/X-1a file, InDesign does not. In InDesign, check the option under Marks and Bleeds (figure 1). Consider saving this as a PDF Preset, so you can easily invoke it on future jobs.

Usually, printers don’t require crop marks, registration marks, etc. Ask your printer what they’d prefer—but if they’ve already neglected to discuss making PDFs, don’t expect an answer.

Figure 1: The PDF/X- 1a option in InDesign doesn’t specify the amount of bleed to include. It’s worth creating a PDF Preset that includes bleed, so you won’t forget it in the future.

EXPORT VERSUS POSTSCRIPT/DISTILL
All Adobe applications can make PDFs via Export or Save As options. There’s usually no need to do it the old-fashioned way—printing to PostScript and cranking up Adobe Distiller to convert the PostScript to PDF. If your printer insists you use that method, ask the reason (some proprietary workflows insert special information into the PDF while distilling). While this process may generate a smaller PDF, the contents are equivalent to an exported PDF.

Beginning with version 6.0, QuarkXPress was no longer dependent on Distiller for PDF creation. Quark licensed the Jaws PDF Library from Global Graphics Software to allow direct export of PDFs. While version 6.0 did not include a formal PDF/X- 1a setting, QuarkXPress 7.0 does.

But if you are using a version of QuarkXPress that is prior to 7.0, how can you replicate PDF/X-1a settings? Here’s how:

• Set image resolution to 300 ppi, compression to High Quality
• Image color space: Ensure that there are no RGB images or other artwork
• Check the font embedding option, and set the subset value to 100 percent
• Include adequate bleed

OTHER PDF CREATION METHODS
Exporting and Distilling are the two best methods for creating PDFs, but there are others.

Here are some cautions about two alternative approaches: Printing to PDF using the Acrobat “printer” as a target is a perfectly legitimate method for creating PDFs, but it uses the current Distiller settings without offering an opportunity to change them. If you’re sure of the Distiller settings, all is well. But you may be setting yourself up for a surprise if you haven’t checked the reigning Distiller job options first.

The Macintosh OS X Save As PDF option (see figure 2) does not invoke Distiller or any other Adobe process. It’s a function of the Mac operating system and doesn’t provide options for image compression, font embedding or niceties such as bleed. Think of it as a glorified screen shot, not appropriate for print.

Figure 2: The built-in Save as PDF function in Macintosh OS X is temptingly easy to use—but the PDFs that it creates are not appropriate for commercial printing.

WHAT’S WRONG WITH THIS PDF?
Now that you’re making perfect PDFs, how can you be sure the PDFs you receive are healthy? If you’re receiving ads or other art files as PDFs, you have no assurance that image content is of sufficient resolution or correct color space. Other subtle problems, such as font embedding issues, are difficult to pinpoint, but can be showstoppers.

The Print Production Toolbar (see figure 3)—introduced in Acrobat 7.0—contains an excellent set of tools for finding and fixing problems in PDFs. Simply choose Advanced > Print Production > Show Print Production Toolbar to view the Print Production tools. You may never use such tools as the Trap Presets or JDF controls, but there are four other tools that are powerful additions to your graphic arsenal:

Output Preview selectively isolates and displays various problems such as RGB images, duplicate spot colors and areas that exceed a specified maximum ink coverage.

Preflight tests a PDF against a profile to find problems such as low-resolution images, font embedding issues or compliance with a standard such as PDF/X-1a. A wide range of prefab profiles ships with Acrobat, and it’s easy to make a custom profile to suit your needs. Additionally, a preflight profile can be saved as a Droplet, which allows batch processing of multiple PDFs automatically.

Convert Colors lets you convert RGB content to CMYK, using your choice of color profile.

Ink Manager remaps one spot color to another, or to a process plate. It also lets you convert spot colors to process equivalents.

The Print Production tools can’t fix everything. Text editing is very limited (often impossible), due to limitations imposed by font vendors. Layout problems like text reflow must be fixed in the original application but, if you receive lots of PDFs created by others and don’t have the luxury of fixing problems in the original application, consider buying dedicated PDF-editing software. Enfocus PitStop (www.enfocus.com) allows you to perform major surgery on a PDF—make global changes to text, even reflow paragraphs. A plug-in for Acrobat Professional, PitStop is the industry standard for PDF editing.

Keep in mind that, given its limited editing capabilities, submitting a PDF as your job file places increased responsibility on your shoulders. It’s up to you to ensure that your original content is healthy, and that you’ve made an appropriate PDF for print. But PDFs can streamline the printing process for both designer and printer, and anything that helps you meet that deadline is a good thing.

Figure 3: These four tools are invaluable for fixing common problems with PDFs. While all the tools perform useful functions, the highlighted tools are the ones you’ll use most often. From left to right: Output Preview, Preflight, Convert Colors and Ink Manager.

SIDEBARS:

Pro Tip: Smaller PDFs
To create smaller PDFs from Adobe Illustrator, turn off Preserve Illustrator Editing Capabilities. It’s on by default, and, in essence, it includes a complete copy of the original Illustrator file inside the PDF, fluffing it up accordingly. Just don’t forget to keep your original Illustrator file as well.

Coming up
In the next column, I’ll explore the advantages (and perils) of placing native Photoshop and PDF files in InDesign and QuarkXPress. In addition, InDesign allows the placement of native Illustrator (.ai) files. Don’t be afraid to go modern: You no longer have to limit yourself to oldfashioned TIFF and EPS files.

Claudia McCue is a consultant, trainer and writer focused on the practical aspects of designing for print. She is author of Real World Print Production (Peachpit Press) and a frequent presenter at industry conferences.