1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
|
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<!-- $Id$ -->
<!DOCTYPE document PUBLIC "-//APACHE//DTD Documentation V2.0//EN" "document-v20.dtd">
<document>
<header>
<title>Apache™ FOP: PDF/A (ISO 19005)</title>
<version>$Revision$</version>
<authors>
<person name="Jeremias Märki" email="jeremias@apache.org"/>
</authors>
</header>
<body>
<section id="overview">
<title>Overview</title>
<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 based on PDF-A-1b and adds accessibility features
(such as Tagged PDF). This format is available within the limitation described on
the <a href="accessibility.html">Accessibility page</a>.
</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>
<p>
PDF/A-1a is enabled by specifying "-pdfprofile PDF/A-1a".
</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>
<p>
For PDF/A-1a, just use the string "PDF/A-1a" instead of "PDF/A-1b".
</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>
<note>
There are additional requirements if you want to enabled PDF/A-1a (Tagged PDF). This is
particularly the specification of the natural language and alternative descriptions for
images. Please refer to the <a href="accessibility.html">Accessibility page</a> for details.
</note>
</section>
<section id="profile-compatibility">
<title>PDF profile compatibility</title>
<p>
The PDF profiles "PDF/X-3:2003" and "PDF/A-1b" (or "PDF/A-1a") 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>
|
