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Citation Software Inc.
Specialists in variable-data publishing since 1986
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www.CitationSoftware.com info@CitationSoftware.com 508-436-2543
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QUESTION: What is PDF/X?
ANSWER: PDF/X is a term
used to refer to a group of technical
standards each of which
describes
a file format that is a subset of the file format described in
Adobe Systems Inc.'s PDF Reference. To put it
another way: a PDF/X file is a special type
of PDF file.
The PDF/X standards have been developed to
facilitate reliable exchange of PDF documents among
graphic-arts professionals.
The Committee for Graphic Arts Technologies Standards
(CGATS)
is the organization responsible for developing the PDF/X standards.
ANSI (the American National Standards Institute) has delegated to CGATS
the task of creating standards for the graphic arts in the USA.
The various PDF/X standards deal with color management
and resource management differently. Some PDF/X standards
have been approved and thus are now considered to be
official standards; others are still in development.
The first version of the PDF/X standard is known as PDF/X-1:1999,
and it was approved by ANSI in December of 1999. The PDF/X-1a
standard was approved in 2001, and the PDF/X-3 standard
was approved in June 2002. Other
PDF/X standards are being developed.
Why do we need PDF/X?
In the graphic-arts community, it often happens that
a PDF file is created by one person and is then
given to somebody else; and the person to whom
it is given is supposed to use the PDF file for high-quality
printing. In this scenario, sometimes the printed result isn't what was
intended. For example,
- the wrong fonts might be used on the printed piece
- the colors might not look the way they are supposed to look on the printed piece.
PDF/X is a way of specifying what needs to happen
when somebody creates a PDF file so that it's
likely to print correctly when they send
it to somebody else. The point of PDF/X is that it gives you a
label to use when asking
for a PDF file if you need to have a high level of
confidence that the document will look exactly the way it's
supposed to look when printed. In other words, you might say to
the person who is creating the file, "Please create the file in PDF/X-1a format."
Doesn't TIFF/IT handle this problem?
For several years now, the graphic-arts industry has depended
heavily on the TIFF/IT file format to ensure reliable reproduction
of graphics. For most graphic-arts professionals today, "TIFF/IT"
is the label to use when asking for a file format that they know
they can rely on for accurate printed reproduction.
The CGATS and DDAP folks believe that the PDF/X standards are going to do for graphic arts
what the TIFF/IT standard has already done - but the PDF/X standards
have an important advantage over TIFF/IT in that TIFF/IT is
completely raster based (so TIFF/IT files tend to be quite large)
whereas PDF/X files can be both vector based and raster based
(which means that - in many cases - PDF/X files are smaller than
TIFF/IT files). It is expected that PDF/X will gradually replace
TIFF/IT over the next several years.
What's in the PDF/X standards?
Each of the PDF/X standards specifies the characteristics that a
PDF file must have in order to meet the criteria set
forth in that standard. For
example, the PDF/X-1:1999 standard says that all colors
must be specified in terms of CMYK, grayscale or spot color.
Thus, a PDF file that specifies colors in terms of RGB
is not a PDF/X-1:1999 file. The PDF/X-1:1999
standard also says that all fonts used in the PDF
file must be embedded in it. Therefore,
a PDF file that uses fonts that it does not contain
is not a PDF/X-1:1999 file.
Creating PDF/X files and verifying PDF/X compliance
The Jaws PDF Creator software
comes with plug-ins and add-ons that are designed for creating PDF/X files.
You can get details about this by clicking
the following links:
www.CitationSoftware.com/GLGR_JawsPDFCreator_PDFX_plug-ins.pdf
www.CitationSoftware.com/GLGR_GWG.pdf
It is important to understand that software geared toward creating PDF/X-compliant files generally cannot guarantee
that each file that's created will actually conform to a particular PDF/X-compliance standard. Such software
will attempt to generate a compliant file, but
the characteristics of the source file (the file that's being converted to a PDF/X
format) determine whether or not the file that gets created will be truly compliant.
For example,
if you want to make a PDF/X-1a file, all colors in the source file must be defined in
terms of CMYK, grayscale, or spot colors. Naturally, this must be taken into account
during the page-creation process — upstream
from the process of generating the PDF/X-1a file.
Because software for creating PDF/X files can't guarantee compliance, you will need software
that verifies compliance. Enfocus Software
offers software products that can handle this task.
How to Get More Information About PDF/X
To learn more about PDF/X, use your Web browser
to visit the following locations:
www.npes.org/standards/subcommittees.html
www.pdfx3.org/faq.html
www.idealliance.org/news/2002/ci0724.asp
www.ipa.org/bulletin/articles/pdfx.php3
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Copyright © 2008 Citation Software Inc.
info@CitationSoftware.com
508-436-2543
www.CitationSoftware.com
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