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<?xml version="1.0" standalone="no"?>
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<!-- $Id$ -->
<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V2.0//EN" "document-v20.dtd">
<document>
<header>
<title>PDF/A (ISO 19005)</title>
<version>$Revision: 389563 $</version>
<authors>
<person name="Jeremias Märki" email="jeremias@apache.org"/>
</authors>
</header>
<body>
<section id="overview">
<title>Overview</title>
<warning>
Support for PDF/A is available beginning with version 0.92.
</warning>
<p>
PDF/A is a standard which turns PDF into an "electronic document file
format for long-term preservation". PDF/A-1 is the first part of the
standard and is documented in
<a href="http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=38920&ICS1=37&ICS2=100&ICS3=99">ISO 19005-1:2005(E)</a>.
Work on PDF/A-2 is in progress at
<a href="http://www.aiim.org/standards.asp?ID=25013">AIIM</a>.
</p>
<p>
Design documentation on PDF/A can be found on FOP's Wiki on the
<a href="http://wiki.apache.org/xmlgraphics-fop/PDFA1ConformanceNotes">PDFA1ConformanceNotes</a> page.
</p>
</section>
<section id="status">
<title>Implementation Status</title>
<p>
<strong>PDF/A-1b</strong> is implemented to the degree that FOP supports
the creation of the elements described in ISO 19005-1.
</p>
<p>
Tests have been performed against jHove and Adobe Acrobat 7.0.7 (Preflight function).
FOP does not validate completely against Apago's PDF Appraiser. Reasons unknown due to
lack of a full license to get a detailed error protocol.
</p>
<p>
<strong>PDF/A-1a</strong> is not implemented, yet. This is mostly because of the requirement
for tagged PDF which is not available in FOP, yet.
</p>
</section>
<section id="command-line">
<title>Usage (command line)</title>
<p>
To activate PDF/A-1b from the command-line, specify "-pdfprofile PDF/A-1b"
as a parameter. If there is a violation of one of the validation rules for
PDF/A, an error message is presented and the processing stops.
</p>
</section>
<section id="embedded">
<title>Usage (embedded)</title>
<p>
When FOP is embedded in another Java application you can set a special option
on the renderer options in the user agent to activate the PDF/A-1b profile.
Here's an example:
</p>
<source><![CDATA[
userAgent.getRendererOptions().put("pdf-a-mode", "PDF/A-1b");
Fop fop = fopFactory.newFop(MimeConstants.MIME_PDF, userAgent);
[..]]]></source>
<p>
If one of the validation rules of PDF/A is violated, an PDFConformanceException
(descendant of RuntimeException) is thrown.
</p>
</section>
<section id="rules">
<title>PDF/A in Action</title>
<p>
There are a number of things that must be looked after if you activate a PDF/A
profile. If you receive a PDFConformanceException, have a look at the following
list (not necessarily comprehensive):
</p>
<ul>
<li>
Make sure all (!) fonts are embedded. If you use base 14 fonts (like Helvetica)
you need to obtain a license for them and embed them like any other font.
</li>
<li>
Don't use PDF encryption. PDF/A doesn't allow it.
</li>
<li>
Don't use CMYK images without an ICC color profile. PDF/A doesn't allow mixing
color spaces and FOP currently only properly supports the sRGB color space. Please
note that FOP embeds a standard sRGB ICC profile (sRGB IEC61966-2.1) as the
primary output intent for the PDF if no other output intent has been specified
in the configuration.
</li>
<li>
Don't use non-RGB colors in SVG images. Same issue as with CMYK images.
</li>
<li>
Don't use EPS graphics with fo:external-graphic. Embedding EPS graphics in PDF
is deprecated since PDF 1.4 and prohibited by PDF/A.
</li>
<li>
PDF is forced to version 1.4 if PDF/A-1 is activated.
</li>
<li>
No filter must be specified explicitely for metadata objects. Metadata must be
embedded in clear text so non-PDF-aware applications can extract the XMP metadata.
</li>
</ul>
</section>
<section id="profile-compatibility">
<title>PDF profile compatibility</title>
<p>
The PDF profiles "PDF/X-3:2003" and "PDF/A-1b" are compatible and can both be
activated at the same time.
</p>
</section>
<section id="interoperability">
<title>Interoperability</title>
<p>
There has been some confusion about the namespace for the PDF/A indicator in the XMP
metadata. At least three variants have been seen in the wild:
</p>
<table>
<tr>
<td>http://www.aiim.org/pdfa/ns/id.html</td>
<td><strong>obsolete</strong>, from an early draft of ISO-19005-1, used by Adobe Acrobat 7.x</td>
</tr>
<tr>
<td>http://www.aiim.org/pdfa/ns/id</td>
<td><strong>obsolete</strong>, found in the original ISO 19005-1:2005 document</td>
</tr>
<tr>
<td>http://www.aiim.org/pdfa/ns/id/</td>
<td><strong>correct</strong>, found in the technical corrigendum 1 of ISO 19005-1:2005</td>
</tr>
</table>
<p>
If you get an error validating a PDF/A file in Adobe Acrobat 7.x it doesn't mean that
FOP did something wrong. It's Acrobat that is at fault. This is fixed in Adobe Acrobat 8.x
which uses the correct namespace as described in the technical corrigendum 1.
</p>
</section>
</body>
</document>
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