16. Strategy

Sooner or later, all audio contents destined for long-term preservation will have to be transferred to digital storage repositories. As the transfer process is time consuming and cost intensive, it should follow a strategy based on the individual situation of the collection and the specific policy of an archive.

Generally, priority should be given to those documents, which are:

  • at immediate risk, and/or
  • part of a commercially unsupported system, and/or
  • in regular demand.

The following analogue carriers can be considered to be inherently unstable and should, therefore, be copied:

  • cylinders
  • instantaneous discs of all types and especially "lacquer" discs
  • acetate tapes
  • all long/double/triple play open reel tape and all cassette tapes of any type
  • any carrier that shows obvious signs of decay either by inherent instability (eg "sticky shed syndrome") or by deterioration caused by improper handling or storage (eg mechanical deformation, mould, etc).

Digital carriers must also be regarded as possibly endangered by decay, especially if they have never been checked for their data integrity. Several formats already show obvious signs of chemical decomposition with the consequent implications for the integrity of the data they contain.

Apart from carrier degradation, recent development suggests that obsolescence and the associated unavailability of replay equipment may become an equal, if not greater threat for the future retrievability of information. Practically all analogue and most dedicated digital audio formats, apart from optical disks, are obsolete. Maintaining the availability of replay equipment will become an ever increasing problem. Sound archives are strongly advised to check their equipment against the size of their holdings and take immediate action to ensure the future availability of sufficient modern (cf paragraph 7) equipment to enable the optimal replay of the entire holdings.

Access copies are to be made whenever possible. In contrast to archival transfers, however, such access or distribution copies may, based on the requirements of clients, be modified by speed corrections, filterings, etc. Data reduction may also be employed when compatible with user requirements. Again, as with transfers to archival masters, careful documentation of all parameters and procedures employed is essential.

Comment:
It must be noted that - with one exception - the above list of carriers does not imply an order of priority. The order of priority of transfer has to be decided for each collection after the carriers have been examined. It will depend on the individual rates of decay of the carriers, the availability of suitable play-back equipment, and, to a lesser extent, the existence of duplicate copies of the material.

The exception is that priority must be given to “lacquer” or “acetate” discs. Even when these discs are playable they are at grave risk of suddenly cracking or crazing without warning. This is because of the steadily increasing stress between the lacquer coating and the supporting base plate. This stress is generated by shrinkage of the lacquer coating. Lacquer discs should, therefore, be given the highest priority in the copying programme.

Format obsolescence is associated with a vanishing market of test equipment including test (calibration) tapes and discs and ancillary accessories such as empty reels, splicing and leader tapes, etc. It is highly recommended to take immediate action to ensure an environment for the optimal transfer of the entire collection.