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This document offers a guide to the important
standards, recommended practices and reference works in the field
of the preservation and conservation of documents of all types.
It does not attempt to include all the publications for a particular
type of document - only the most important ones. The level of
authority of the publications varies. They range from de-facto
standards that are widely accepted by the practitioners in the
field to formal International Standards produced by the International
Standards Organisation (ISO). International cooperation
in standardisation work is generally coordinated by ISO which
defines itself as:
" - - a worldwide federation
of national standards bodies (ISO member bodies). The work of
preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject
for which a technical committee has been established has the right
to be represented on that committee. International organisations,
governmental and nongovernmental, in liaison with ISO,
also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (TEC) on all matters
of electrotechnical standardisation."
A standard can be used either as a guideline
or as a source of specifications. Standards by themselves, however,
are only an introduction to the subject. In the use of a standard
it is important that the user is familiar with the subject in
question, thus being able to relate the information and the circumstances
to each other. In particular, standards and other publications
must not be used as the sole source of information about conservation
techniques. Seek advice from experts and practitioners in the
field before trying to conserve any document. Much protection
can be offered by ensuring that documents are stored in appropriate
containers, are not subject to fluctuations of temperature and
relative humidity and are handled with care. Specialist treatment
is available for all types of document, from the most ancient
to the most recent, and professional advice should be sought from
appropriate museums, libraries and archives before undertaking
any work on them. Specific advice is also often available in
the standards quoted.
Standards are very important, but unfortunately
standards often become modified by users after some time which
can make the standard out-dated and even impede the easy exchange
of information. A good example of this are the Machine Readable
Cataloguing Formats (MARC) which are all based on the ISO 2709-1981
standard. However, many countries have developed their own national
version and this makes the exchange of bibliographic records more
difficult. Other examples include the many Document Type Definitions
(DTDs) which are based on the SGML standard.
The documents in the archives and libraries
of the world are indispensable sources for many scholarly disciplines.
They are also sources for more informal purposes: self-education,
entertainment and general interest. No evaluation of politics,
history, everyday life, music and performing arts would be possible
without these documents.
Information should be available to all people as freely and as easily as possible. Preservation of that information in all formats ensures access and should be pursued actively for that reason.
The safeguarding of all these documents
has until recently been primarily associated with the keeping
of books and other written materials. This is partly, perhaps,
because textual libraries have existed for more than 4000 years,
while audiovisual archives have been in existence for only
less than 100 years. The newest forms of document have been in
common existence for less than a decade. There are, however,
fundamental differences between the different types of documents.
Printed matter represents human thoughts
by the use of a stock of symbols. A certain amount of redundancy
is intrinsic in speech and writing. Letters, sometimes even words,
may be omitted without any real detriment to communication. Good
examples are the scripts of Semitic languages which generally
do not represent all vowels which are spoken. But still, even
complex texts like philosophical tracts can be communicated by
these languages.
In contrast, the audiovisual document
is an analogue representation of a physical status or event: every
part of such a document is information. While a speck of mould
in a book does not normally hamper the understanding of the text,
comparable damage on a photograph would cover up information,
and, on a magnetic tape, it could even render the tape unreadable.
Seen, therefore, from the perspective of redundancy, audiovisual
documents call for a higher degree of protection and security
than written materials. Digital data can also be similarly endangered.
The modern electronic documents are to
some extent insubstantial - many exist for part of the time only
as a pulse of energy (for example, E-Mail messages passed over
a telephone wire). They do, however, have certain safeguards built
into them to help ensure the safe and complete arrival and storage
of a message. They also have to be stored at some point on a physical
carrier for later access.
One factor that most, if not all documents,
have in common is their reliance on polymeric materials. The traditional
materials of paper, parchment, leather, palm leaves etc. are all
natural polymers. The newer media of tapes, discs and films rely
on man-made polymers such as PVC and polyester. The rate of chemical
de-composition of the various polymers varies greatly. Some will
last - and have lasted - for millennia; others may struggle to
survive for a decade.
All polymers decay. The decay cannot
be stopped - but it can be slowed down by careful handling and
favourable storage. It can also be greatly accelerated by careless
handling and poor storage. All the storage conditions given in
standards and other publications are for guidance. If the conditions
are met, the decay does not stop. The figures quoted for temperature
and humidity levels are a compromise between the rate of decay
on the one hand and the costs of maintaining the conditions, of
transfer and of conservation on the other. The conditions can
be relaxed but at the expense of more rapid decay.
Format of the Guide
The various types of documents covered
in this guide are divided into five groups:
Paper and Other Traditional Materials
Photographic and Micrographic Materials
Mechanical Carriers
Magnetic Materials
Optical Materials
There is an additional chapter covering
the particular problems of preserving Electronic Publications,
Electronic Documents and Virtual Information plus chapters giving
some general preservation information and a glossary.
The Paper and Other Traditional Materials
group include paper, parchment, leather and palm leaves. Seals
are also included in this group. This is the oldest and largest
group of documents.
The Photographic Materials group
include all types of still photographic images - black and white
and colour; negative and positive; transparency and print - on
all types of carriers - paper, glass, cellulose and other materials
and includes micrographs of all types.
The Mechanical Carriers group
covers sound recordings on cylinders and discs.
The Magnetic Materials group include
all forms of magnetic material - tapes, hard discs and floppy
discs.
The Optical Materials group includes
all laser read and written materials including CD-Audio, CD-ROM,
CD-Recordable, magneto-optical disks and optical tape.
This guide is a compilation of contributions
from a number of people, each expert in the preservation of a
different type of document. Each field of expertise has developed
its own terminology and, while there are many terms shared by
all the disciplines, some are not. No attempt has been made to
harmonise the terms used and so you will find different terms
used in different chapters
but meaning the same thing eg. user copy and access copy.
You will also find places where the
topic has been covered in another chapter as well. Again, efforts
have not been made to avoid this. Many readers will wish to read
a chapter in isolation and this repetition will ensure that they
receive all the information necessary for the understanding of
the chapter.
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