ever, only the new PDF/A standard can
guarantee that users will be able to view ex-
actly the same content as when their docu-
ments were created. 周is format brings the
kind of legal certainty that can be decisive
in many business and administrative con-
Why PDF/A and not PDF?
Why has a special PDF standard now been
deﬁned for archiving documents? Are tra-
ditional PDF documents not ‘good enough’
for long-term archiving? PDF has some
excellent characteristics that lend them-
selves to the creation of archive docu-
ments. Like a container, a PDF can incor-
porate completely diﬀerent elements such
as text, images, and fonts. In addition, it
reproduces layouts that are true to the
original and is cross-platform capable.
However, certain requirements must be
met in order to enable the exact reproduc-
tion of content.
■■Required: One ‘must’ is that users re-
quire full access to all elements belong-
ing to a document. For example, fonts
must be embedded – a link to the font in
question is not sufficient. This means
that if, in 10 years time, a user who tries
to open a document does not have a re-
quired font on his or her computer, spe-
cial characters or symbols will not be dis-
■■Prohibited: In addition, some PDF fea-
tures must be avoided. Such elements are
prohibited because they would undermine
the required document durability, and in-
clude interactive elements and PDF layers.
周ese features inhibit the unambiguity that
is required from an eﬀective PDF/A ﬁle.
For example, in the case of a PDF docu-
ment with layers, users printing it out in 50
years time might well ask themselves which
layers are valid and which are not. 周is
kind of decision needs to be made now –
when the PDF is created.
A PDF/A document is basically a tradi-
tional PDF document that fulﬁlls precisely
deﬁned speciﬁcations. In order to prevent
users from repeatedly having to test and
discuss the best appearance of a well-
functioning archive PDF, industry experts
decided in 2002 to work together to de-
velop the PDF/A standard.
The introduction of the PDF/A standard
周e PDF/A standard for long-term ar-
chiving was adopted by ISO (International
Organization for Standardization) in au-
tumn 2005. 周e PDF/A standard was pub-
lished with the number ‘ISO 19005-1:2005’
and is based on PDF speciﬁcation 1.4. An
additional part, PDF/A-2, is currently be-
ing prepared. 周is part shall refer to PDF
周e PDF/A standard aims to enable the
creation of PDF documents whose visual
appearance will remain the same over the
course of time. 周ese ﬁles should be so晴-
ware-independent and unrestricted by the
systems used to create, store, and repro-
duce them. As far as PDF/A is concerned,
practice soon caught up with theory.
While Acrobat Professional 7 contained
only ‘dra晴’ PDF/A functions, Acrobat 8,
which has been available since the end of
2006, now oﬀers creation and veriﬁcation
features that comply with the adopted
Many new PDF/A tools and solutions
for creating and verifying ﬁles have en-
tered the market since the introduction of
the standard – from ‘small’ tools for indi-
vidual users who want to create PDF/A
documents every now and again to exten-
sive server solutions that can create a hun-
dred thousand archive documents from
databases in just a few hours time.
ISO is an international organization for
standardization, active primarily in tech-
nical and electronic fields. The PDF/A stan-
dard was developed by industry and de-
PDF/A has two levels of compliance:
PDF/A-1a (Level A) applies to semantic correctness
and structure. Each character must have a Unicode
equivalent. The structure is expressed by tags.
PDF/A-1b (Level B) applies to visual integrity.
Any ﬁle that meets the requirements for PDF/A-1a will
also comply with PDF/A-1b, which is less strict.
International companies and experts from
the field of PDF technology have joined
forces to form the PDF/A Competence Cen-
ter. It aims to promote the exchange of in-
formation and experiences relating to
long-term archiving. Users can visit
www.pdfa.org for up-to-date advice and
background information as well as a dis-
cussion forum on PDF/A.
Durable documents with the PDF/A standard
in a Nutshell