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Metadata
Many current file formats allow the storage
of metadata. Metadata is data passed for a
document over and above the actual work-
ing data. 周is might include technical in-
formation (for example, a digital camera
saves additional information called EXIF
data for each image file, including the ex-
posure, aperture, and focus). In addition,
users can add descriptions to files later on,
such as keywords or copyright notices.
IPTC metadata, primarily used by profes-
sional photographers, has been around for
years.
Many programs allow metadata on a file
to be viewed or even changed in the ‘Prop-
erties’ area. 周is normally includes core
information such as the title of the docu-
ment, the author, and the program used to
create it.
Metadata provides useful information
that can simplify the organization of large
numbers of digital documents, either in
database solutions or using search func-
tions. Metadata is particularly important
for archiving, since it can provide infor-
mation on a person or place depicted in an
image, the author of a document, and any
copyright restrictions.
PDF/A and metadata
Many issues relating to the use of meta-
data when creating valid PDF/A docu-
ments are le晴 to the decision of the user.
However, the following directives apply:
■■One metadata field is mandatory: 周e
PDF/A identifier. 周is identifier is nor-
mally automatically written to the relevant
field in its correct form by the PDF/A con-
verter used to create the PDF/A document
in question.
■■All metadata attached to a PDF file
must exist in a certain form and must be
encoded in an XMP-compliant manner.
Although PDF/A only stipulates a single
mandatory field, it makes sense to make
the most of the possibilities of XMP to en-
able efficient archiving and powerful
search and sorting functions.
What is XMP?
Metadata is another topic where standards
are important. 周is type of data cannot be
used effectively if every single user or user
group develops their own system for cre-
ating and managing additional informa-
tion. In the case of metadata systems that
already exist in parallel, a reliable method
for converting one to the other must be
provided at the very least.
To promote the standardization of
metadata systems, Adobe Systems is now
using the Extensible Metadata Platform
(XMP). XMP is a procedure that acts as a
kind of bracket that pulls together estab-
lished metadata formats such as IPTC and
EXIF. Acrobat Professional and Adobe
Reader are two of the applications that
display XMP metadata; Acrobat Profes-
sional also allows it to be edited. Other
manufacturers also use XMP – the tech-
nology is not limited to Adobe.
Viewing and editing PDF metadata in Acrobat
Metadata can be viewed at the following
menu path: ‘File’ → ‘Properties’. 周e ‘De-
aoe
XMP uses the RDF to embed
meta information in binary
data. RDF stands for Resource
Description Framework and is
a formal language for staging
metadata on the Internet.
To promote the use of XMP,
Adobe provides the XMP speci-
fication and a software devel-
oper kit under an Open Source
license for use by all.
Internet: www.adobe.com/
products/xmp
Analog metadata: Metadata also occurs in
the analog world in the form of informa-
tion such as imprints and mastheads for
books and journals.
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PDF/A
in a Nutshell
PDF/A applications in everyday life
