PDF/UA in a Nutshell

21 Pages·2013·0.83 MB·English

PDF/UA
in a Nutshell
Accessible documents with PDF
Olaf Drümmer
and Bettina Chang
■ The ISO standard for
universal accessibility
■ Laws and regulations
■ The history of PDF/UA
■ File format requirements
■ Compliant PDF programs
■ Assistive technology
■ PDF/UA creation tools
■ Validating PDF/UA
compliance
■ What the experts say
Contents
PDF/UA: The ISO standard for universal accessibility 3 Assistive technology for in-depth testing 14
Compliant reader software 14
PDF/UA: The key facts 4
Laws requiring accessible IT services 4
Added value for PDF users 15
Introduction to the Web Content Accessibility Guidelines 2.0 4
Visual or motor impairments 15
Reading and writing difficulties 15
Important Laws and regulations 5 Easier reading and navigation on mobile devices 15
International 5
United States of America 5 The potential benefits of PDF/UA 16
Europe 5
Laws paving the way for PDF/UA 17
The history of PDF/UA 6
What the experts are saying 18
PDF/UA’s requirements 7
Klaus-Peter Wegge, Siemens AG 18
File format requirements 7
Markus Riesch, “Access for All” 18
Requirements for compliant PDF programs 8
Requirements for compliant assistive technology 8
Learn more about PDF/UA 19
PDF/UA Competence Center 19
Accessible PDF: Users and usage 9
PDF/UA seminars 19
PDF Association membership 19
PDF/UA: Creation tools 10
AIIM PDF/UA Committee 19
Table 1: PDF/UA creation tools 10
Validating PDF/UA compliance 12
Table 2: Validating PDF/UA compliance 13
PDF/UA in a Nutshell I
Introduction
PDF/UA: The ISO standard for
universal accessibility
Information plays a central role in soci- PDF/UA-1 is the first part of the
ety today, and it is becoming more and PDF/UA standards family; the “UA”
more common for that information to suffix stands for “Universal Accessibili-
be offered in digital form alone. The re- ty” and refers to the standard’s central
liable, user-friendly Portable Document requirement. It is the first complete defi-
Format (PDF) has become the world’s nition of a set of requirements for uni-
file type of choice for providing infor- versally-accessible PDF documents.
mation as a digital document. PDF/UA is aimed primarily at de-
Tags can be added to a PDF in order velopers of software for creating, read-
to structure the content of a document. ing, editing and validating PDF, and at Tagged PDF:
These tags are a critical requirement if suppliers of assistive technology. The Tags are standardised content
any form of assistive technology (such standard itself is not intended as a field markers in a digital document.
as screen readers, specialist mice, and manual for day-to-day use, but for PDF First available in Adobe Acro-
speech recognition and text-to-speech creators looking to learn more. The PDF bat 5, tags can be used to cre-
software) is to gain access to this con- Association and its members offer spe- ate a PDF file with a logical
tent. To date, PDF documents have rare- cialist articles, webinars and training, document structure . Tags are a
ly been tagged, and not all software can providing detailed information about critical requirement for access-
ing the content in PDFs with
make use of PDF tags. In practical terms, PDF/UA and explaining how to create
assistive technology.
this particularly reduces information‘s accessible PDF content. Implementing
accessibility for people with disabilities the clearly-defined requirements of the
who rely on assistive technology. PDF/UA standard in software products
will allow users to easily create accessi-
ble PDF documents without any special
training, opening up effortless access to
high quality content to as many people
as possible.
At the time of PDF/UA’s publication,
of course, there were no programs avail-
able which were fully compliant with the
standard. Since then, however, a number
of software developers including Adobe
The ISO (International Organization for Standard-
ization) is the largest organisation in the world for Systems, axaio software, callas software,
developing and publishing international standards. NetCentric Technologies, NV Access,
PDFlib, xyMedia, the Swiss National
In order to ensure future access to Association of and for the Blind (SNAB),
PDF documents for as many people and the Swiss foundation “Zugang für
as possible, the ISO 14289-1 standard alle” (Access For All) have already an-
(known as PDF/UA) was developed by nounced or even released products sup-
specialists from around the world. It was porting the PDF/UA format.
published by the ISO in July 2012 with More and more developers, govern-
the official title “ISO 14289-1. Document ment authorities and other organisa-
management applications – Electronic tions are expected to accept PDF/UA as
document file format enhancement for an absolute requirement for universally
accessibility – Part 1: Use of ISO 32000-1 accessible PDF documents from this
(PDF/UA-1)”. point on.
PDF/UA in a Nutshell 3
Introduction
PDF/UA:
The key facts
What does “universal accessibility” from websites, this applies in particu-
actually mean when it comes to PDFs? lar to PDF documents. Although such
It is the idea that everyone should be laws do not always apply to the private
equally able to independently access sector (or apply only in limited cases),
and use the information contained more and more modern businesses are
within a PDF document. This applies accepting their responsibility to pro-
in particular to people with disabili- vide accessible versions of both their
ties and those with other difficulties; websites and the PDF documents they
in other words, those who particularly provide.
depend on universally accessible infor-
Introduction to the Web Content
mation and documents. The PDF/UA
Accessibility Guidelines 2.0
standard allows these people the fol-
lowing key options: The requirements for PDF/UA are
based on the principles of Version 2.0
■ Making use of PDF documents with- of the W3C consortium’s Web Content
out assistance from others Accessibility Guidelines (WCAG), also
published in identical form as an ISO
■ Reaching a specific goal easily, di- standard in October 2012 (ISO/IEC
rectly, and within a reasonable time 40500). WCAG 2.0 guides the creation
frame of accessible web content, focusing on
the kinds of content and applications
■ Making the same-quality use of PDF usually provided on websites.
documents as people without disa- Some WCAG 2.0 tips of a purely in-
bilities. formative nature suggest how barriers
to access can also be avoided in PDF
The technical requirements for uni- documents, but a systematic explana-
versally accessible PDF documents are tion or guide is not provided. PDF/UA,
described clearly and in full in the new on the other hand, exclusively and ful-
PDF/UA standard. They define, for ex- ly addresses the PDF format, bringing
ample, how to create text, images, form the ideas behind WCAG 2.0 into the
fields, lists and tables that can be used world of PDF and setting PDF-specific
by people with disabilities. rules.
As an ISO standard, PDF/UA does
Laws requiring accessible IT services
not offer concrete help with implemen-
These requirements are increasingly tation, either for specific programs or
important for businesses and public areas of application. This, however, is
institutions, as current legislation re- covered by the PDF/UA Competence
quires (and in some cases has regulat- Center founded by the PDF Associa-
ed for many years) universal accessi- tion. The PDF/UA Competence Center
bility in information technology. Laws is made up of leading international
in the USA, Canada, Australia and the businesses and individual experts who
European Union, for example, require use the website www.pdfa.org, as well
state and federal authorities to allow as publications, seminars and confer-
the public universal access to the dig- ences, to provide information about
ital information they provide. Aside implementing PDF/UA in practice.
4 PDF/UA in a Nutshell
Laws and regulations
Important Laws and
regulations
International
Section 11 of the German federal law
BGG has required since 2002 that fed-
■ UN Convention on the Rights of People eral authorities’ online presences and
with Disabilities: The UN Convention on services be universally accessible. Some
the Rights of People with Disabilities German states also have state-level laws
defines in concrete terms the general which place similar requirements on lo-
human rights of people with disabilities. cal authorities.
It has been in effect since 2008.
■ Regulation for the creation of univer-
sally accessible IT in accordance with the
United States of America Equal Treatment of Disabled Persons Act
(Barrierefreie-Informationstechnik-Ver-
■ Americans With Disabilities Act (ADA): ordnung – BITV 2.0): BITV 2.0 specifies
In 1990, the US Congress passed a fed- the minimum requirements for online
eral law, ADA, which forbade all forms information and services provided by
of discrimination based on disability. federal authorities. They are most-
ly based on the recommendations of
■ Rehabilitation Act, Section 508: In WCAG 2.0. Some German states have
1998, the United States expanded the comparable state-level regulations re-
Rehabilitation Act to include Section garding universally accessible IT ser-
508. Since then, the federal govern- vices.
ment has been required to ensure that
all its IT services are accessible for peo- ■ Regulation on equal rights for disabled
ple with disabilities. persons (Behindertengleichstellungsver-
ordnung, BehiV): Article 10 of the Swiss
federal regulation BehiV requires fed-
Europe
eral authorities to make anything they
provide online universally accessible Important Standards:
■ EU Mandate 376: With Mandate 376, so that people with disabilities can PDF/UA (ISO 14289-1:2012): ISO
the European Commission tasked the make use of it. standard 14289-1 defines all
standardisation organisations CEN, essential requirements for uni-
CENELEC and ETSI with harmonising ■ Federal Guidelines for Designing versally-accessible PDF docu-
European public procurement laws. Universally Accessible Online Content ments, PDF programs and as-
They are currently working on the EN (P028): The Swiss P028 guidelines re- sistive technologies for using
PDF/UA.
301459 standard which specifies re- quire federal websites to conform to
quirements for universal accessibility WCAG 2.0 and to meet compliance PDF 1.7 (ISO 32000-1:2008):
in creating public-sector ICT products level AA. ISO standard 32000-1 specifies
and services. the PDF file format.
■ Federal Law on the Equal Treatment of
WCAG 2.0 (ISO/IEC 40500:2012):
■ European Accessibility Act: The Euro- Disabled Persons (Bundes-Behinderten-
ISO/IEC 40500 is a standard
pean Commission is currently prepar- gleichstellungsgesetz – BGStG): The Aus-
which is identical in content to
ing a European Accessibility Act. trian federal law BGStG requires the
the W3C’s WCAG 2.0, the guide-
Austrian federal government to make lines for a universally-accessi-
■ Equal Treatment of Disabled Persons Act its services available in an accessible ble web.
(Behindertengleichstellungsgesetz – BGG): form.
PDF/UA in a Nutshell 5
History
The history of PDF/UA
Timeline: From PDF to PDF/UA The first version of PDF, PDF 1.0, was World Wide Web Consortium (W3C)
1993: Adobe Systems publishes released in 1993. PDF was created and published WCAG 2.0. This replaced its
PDF 1.0 further developed by Adobe Systems predecessor WCAG 1.0, published in
Incorporated. The PDF format makes 1999, and took into account the tech-
1999: W 3C releases Web Content
it easier to exchange and display digital nical developments which had taken
Accessibility Guidelines 1.0
documents; in the two decades since place since that time.
2001: PDF 1.4 integrates tags to
its publication, it has gained world- An ISO standardisation project be-
represent the logical
wide acceptance. It allows all kinds of gan in 2009. Based on AIIM’s pro-
structure of content
documents to be reproduced exactly as ject, ISO committee ISO  TC  171
within PDF documents
they were originally designed, regard- SC  2, chaired by Cherie Ekholm of
2002: Equal Treatment of less of the platform used, thanks to a Microsoft, aimed to further develop
Disabled Persons Act, number of (sometimes free) PDF cre- PDF/UA. A wide range of companies,
Germany ation and viewing programs and web including Adobe, Microsoft, callas
2002: A ccessible IT Regulation 1.0, browser plug-ins. software, Design Science, NetCentric
Germany For a long time, however, this file and others were actively involved in
format remained inaccessible to a large the standardisation work. This meant
2004: PDF/UA project begins,
number of people, as PDF originally that just one year later, the draft stand-
coordinated by AIIM
focused on the visual presentation of ard ISO/DIS 14289-1 was ready for
2008: P DF 1.7 published as an a document rather than its content publication. After an intensive consul-
ISO standard (ISO 32000) and structure. In order to address this tation and testing phase, PDF/UA was
problem, in 2001 Adobe introduced finally approved as an ISO standard
2008: U N Convention on the
Rights of People with tags with PDF 1.4 and Adobe Acrobat and published as ISO 14289-1 in July
Disabilities comes into 5. These can be used to turn a conven- 2012.
effect tional PDF into a tagged PDF. The German standardisation organ-
In 2004, a working group began to isation DIN (Deutsches Institut für
2008: W3C releases Web Content
form, coordinated by AIIM (the As- Normung e.V.) is currently working on
Accessibility Guidelines 2.0
sociation for Information and Image translating ISO 14289-1 into German;
2009: I SO takes over the PDF/UA Management, www.aiim.org), aiming this version is expected to be published
project as ISO/NWI 14289 to develop a universally accessible PDF in autumn 2013.
standard. This standard would speci- On the international stage, mean-
2011: A ccessible IT Regulation 2.0,
Germany fy a complete set of requirements for while, the second part of the standard
tagged PDF documents that could be (PDF/UA-2) is now being prepared by
2012: I SO approves and
reliably used to create and check for a the ISO. PDF/UA-2 will be based on
publishes PDF/UA
sufficient level of accessibility. the next version of the PDF format,
(ISO 14289-1)
A further important development PDF 2.0, and will make use of all that
came in 2008, when Adobe’s PDF 1.7 has been learned during the develop-
specification became an ISO stand- ment and introduction of PDF/UA-1.
ard – published by the ISO as “ISO Among other things, it will include
32000-1:2008. Document management more extensive options for sophisti-
– Portable document format – Part 1: cated semantic structuring of con-
PDF 1.7”. A copy of the standard can tent and support for specific tag sets.
be downloaded for free from the Adobe These will include scientific sets, such
website, while the ISO version (which as MathML and ChemML, as well as
is identical in content) can be ordered specialised publication tag sets such as
from ISO for a fee. Also in 2008, the DAISY and DocBook.
6 PDF/UA in a Nutshell
Requirements
PDF/UA’s requirements
The PDF/UA standard defines technical are used, a role assignment entry must
requirements for universally-accessible record which standard tag each one rep-
PDF documents by identifying a set of resents.
relevant PDF functions (including text
content, images, form fields, comments, ■ Information may not be conveyed
bookmarks and metadata) based on ISO using visual means alone (e.g. contrast,
32000-1 (PDF 1.7) and specifies how colour or position on the page).
they should be used in PDF/UA-com-
pliant documents. It does not address ■ No flickering, blinking or flashing
elements which have no direct impact content is permitted, either as effects
on accessibility, such as the compression controlled by JavaScript or as part of any
algorithms used for image data. videos embedded within the PDF.
Successful access to content within
PDFs depends not just on compliant ■ A document title must be given, and
documents, but also on compliant PDF the document must be set up so that the
programs and assistive technology. title (rather than the file name) appears
PDF/UA therefore also specifies require- in the window title.
ments for these. A brief selection of the
main requirements is shown below: ■ The language of all content must be
noted, and changes of language must
File format requirements
be explicitly marked as such.
■ Content is categorised in one of two
ways: meaningful content, and artefacts
such as decorative page elements. All
meaningful content must be tagged and
integrated into the structure tree of all
tags within a document. Artefacts, on
the other hand, need only be marked as
such.
■ Meaningful content must be marked
with tags and, together with the other
tags in the document, create a complete
structure tree.
■ Meaningful content must be marked
with the appropriate semantic tags.
■ The structure tree created by the doc-
ument tags must reflect the document’s
logical reading order.
■ Only the standard tags defined in
PDF 1.7 may be used; if any other tags
PDF/UA in a Nutshell 7
Requirements
■ Any pictorial elements – whether ■ It must not limit the functionality of
image objects or other non-text objects the assistive technology.
such as vector objects or object groups
– must have corresponding alternative ■ It must allow the assistive technology
text. to recognise the language used and any
changes in language within the document.
Adhering to these technical and se-
mantic requirements will create a uni- ■ It must allow navigation through the
versally accessible PDF/UA document document by page number, through the
which a person with disabilities can structure tree, or through bookmarks.
make use of just as effectively and in
just as high quality as any user without ■ It must not play media content auto-
disabilities. matically, but rather wait for the user’s
command to do so.
Requirements for compliant PDF
programs Requirements for compliant assistive
technology
PDF programs are often the link for
people with disabilities between the The term “assistive technology” de-
PDF document to be read and any as- scribes anything which helps or allows
sistive technology that may be used. In people with disabilities or other dif-
practice, this means that PDF/UA-com- ficulties to use any kind of hardware
pliant PDF programs must hand over and software. People with serious
all content and other information from visual impairments may use screen
the PDF document to the assistive soft- magnifiers. People with restricted
ware or device, and that the assistive mobility can use joysticks or special
technology itself must make use of all keyboards for input and navigation.
the information it receives, including Highlighting the current portion of a
for navigation, filling out form fields, or document while also reading it aloud
reading metadata. using a text-to-speech function can
make it easier for users with dyslexia
■ The software must be able to read and to read a document. Blind users often
pass on all information stored within use a standard keyboard for input and
the document’s tags and structure tree, navigation alongside a screen reader
or otherwise make all the document’s or Braille display for output. For all
content accessible. of these assistive technologies to work
properly with PDF/UA, they must
■ It must make all content available meet the following requirements:
to the assistive technology, including
structural information. ■ They must be able to recognise all
structural elements, attributes and key
values used in the specification and
output them for the user of a PDF doc-
ument.
■ They must allow the user to navigate
through the document by page number,
through the structure tree, or by using
bookmarks.
■ They must allow the user to easily set
and change the magnification of a PDF
document at any time.
8 PDF/UA in a Nutshell
Usage
Accessible PDF:
Users and usage
As a quality standard for universal- terms of functionality, compatibility
ly accessible PDF documents aimed and accessibility, it is often easier for
at both software developers and doc- everyone involved to export these doc-
ument creators, PDF/UA serves as a uments to PDF format before passing
clear basic requirement for everyone them along to others. PDF documents
involved in PDF creation. It gives soft- created in this way are not automati-
ware developers a clear set of goals to cally PDF/UA-compliant, but it is now
work towards implementing which us- becoming much easier to make these
ers can then take into account when documents universally accessible and
creating PDFs. ultimately, for them to meet the stand-
This benefits all PDF creators. Some ard.
of them will find PDF/UA compliance A further area of application for
brings significant advantages. This in- PDF/UA is in digital distribution of
cludes people who work with office printed publications in PDF format. The
documents, who often distribute their print data is usually prepared in digital
finished presentations, spreadsheets format using layout and editing pro-
and text documents to others or store grams, then exported in PDF format for
them in a central location for others printing. These programs are also often
to retrieve. As the office program each used to generate a PDF for on-screen
person uses can vary dramatically in reading which is then distributed over
the web or by email. The most exten-
sive support for universally accessible
PDF documents can be found in the
layout program Adobe InDesign, from
version CS 5.5 onwards. InDesign pro-
vides a particularly high level of support
for the technical requirements behind
the PDF/UA standard , which means it
requires little extra work to create uni-
versally accessible PDF/UA-compliant
documents. Certain aspects may need
occasional adjustment, either manually
or with the use of specialist software ex-
tensions.
If a PDF document is created from a
database, XML, or some other struc-
tured data set, the solutions used can
also take advantage of updated PDF
programming libraries which encode
the content in accordance with PDF/UA
specifications. It is also equally possible
to adapt solutions which already allow
the creation of tagged PDFs, in order to
produce PDF/UA-compliant PDF docu-
ments.
PDF/UA in a Nutshell 9
Software tools
PDF/UA:
Creation tools
In principle, universally-accessible PDF adaptation process must then be started
documents can either be generated di- again from scratch.
rectly during document creation, using a The direct approach is almost always
suitable program, or indirectly generated the better option; post-creation PDF ed-
by adapting an existing PDF document. its should be avoided or at least kept to a
The indirect approach tends to require a minimum. Either way, it is essential that
great deal of work, as all tags and numer- the document creation program can per-
ous other settings will need to be provid- form the functions required and that the
ed manually. document creator can make use of them.
This work can also become void as soon Although only a few programs current-
as a new version of the PDF document re- ly support PDF/UA in its entirety, a wide
places the old one, if any changes to the range of options still exist in the form of
document’s content need to be made. The the programs listed alphabethical below:
Table 1: PDF/UA creation tools
Software Developer Application PDF/UA functions supported
Adobe Acrobat XI Adobe Systems PDF document creation, • Create and edit content tags
Pro editing and viewing • Mark page content as artefacts
• Add alternative text
• Specify the language(s) used for a document and
specific content within it
• Feature to add basic accessibility to any PDF
• Fast, extensive accessibility checking
Adobe Distiller Adobe Systems Converts PostScript files • Create tagged PDFs
Server 8 to PDF • Requires specific pdfmark codes within the Post-
Script files
axesPDF for Word xyMedia Add-in for Word 2007 • Specify the language of a document
and Word 2010. Helps • Set up a series of tabs based on the document struc-
the user to use Word ture
functions and compen-
• Specify the document title and include it in the doc-
sates for weaknesses and
ument window
errors resulting from ex-
porting a tagged PDF • Use all standard PDF tags
from Word. • Advanced table tagging
• Tag all content or mark it as an artefact
• Integrated validation function
CommonLook NetCentric Tech- Plug-in for Word and • Guided review of document based on checkpoints
Office 1.2 nologies PowerPoint. It uses • Adjust alternative text for images
checkpoints to take us-
• Correct mappings between styles and tags
ers through the author-
ing software’s accessibili- • Advanced table tagging
ty functions • Enhanced tagged PDF export
• Generate bookmarks
• Support for accessible PDF forms
10 PDF/UA in a Nutshell