1.4 Content, organisation, bibliography and citations

TC 05 concentrates on measures to optimise conditions for the preservation of physical and chemical integrity of traditional, haptic audio and video carriers. It concentrates on those carriers of recording systems that have been accepted by the market, and form 99% (or more) of all audio and video collections. It is not a handbook of audiovisual recording systems. Therefore, it does not discuss the vast variety of instantaneous audio discs, or rarely used recordings systems like magnetic wire or steel tape, Philips-Miller, Selenophone, etc., and mechanical video discs such as TED. The mainstream recording systems, however, are explained to some degree, in order to provide a basic understanding of the specific function and features of carriers: why and how handling and storage could negatively or positively influence their physical and chemical integrity, and what influence damage and/or deterioration processes would have on signal retrieval.

TC 05 is not a catalogue of mere Dos and Don’ts. Optimal preservation measures are always a compromise between many, often conflicting parameters, superimposed by the individual situation of a collection in terms of climatic conditions, the available premises, personnel, and the financial situation. No meaningful advice can be given for all possible situations. TC 05 explains the principal problems and provides a basis for the archivist to take a responsible decision in accordance with a specific situation. This is the reason why, for example, climatic storage ranges are recommended rather than strict figures, which often trigger a false feeling of security, whereas each chosen value is only a compromise. This is also the reason why TC 05 does not provide a general “Code of Practice”, as this would hardly fit the diversity of structures, contents, tasks, environmental and financial circumstances of collections. However, archives are strongly encouraged to develop and codify, within the limits of physical and chemical constraints, their specific rules of procedures.3

This set of guidelines is broadly divided into two main parts. The first part (Section 2), explains the main types of audio and video carriers, their composition and recording principles, physical and chemical stability, and deterioration caused by normal replay.

The second part (Sections 3–5), advises on best practice for passive preservation through careful handling and appropriate storage and transport conditions.

It should, finally, be noted that cleaning and restoration of carriers is not part of this publication. These aspects are part of signal extraction and discussed in IASA-TC 04, chapter 5. The bibliography lists books and articles, including electronic information, which have become the “mainstream” of audiovisual preservation literature. Generally, the information and recommendations of this publication that are based on common and undisputed knowledge are not specifically referenced. However, references are given when — because of new experiences or information, or research — new recommendations are made or deviations from the mainstream of earlier recommendations are suggested. In addition, it should be noted that this book also contains primary source information: observations and appraisals based on the experiences of the authors gathered over years and decades.

As these guidelines concentrate on handling and storage, there is generally no discussion of variants and discrepancies between publications concerning composition and/ or deterioration of materials.

Cross-references to IASA-TC 04 are made to the second edition (2009) of these guidelines.

3. The British Library National Sound Archive Code of Principles may serve as a structural example. In A.Ward 1990, Appendix 1.