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.
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.
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.
