15. Prioritisation

Sooner or later, all sound and audiovisual content destined for long-term preservation will have to be transferred to file-based 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 that are at greatest risk, through either degradation or technical obsolescence (see sections 3 and 4).

Carriers likely to degrade due to inherent instability, age or improper handling may include:

  • wax or celluloid cylinders
  • nitrate film
  • instantaneous audio discs of all types, especially “lacquer” discs
  • acetate tapes
  • acetate film showing signs of colour fading, unless stored frozen
  • ½” EIAJ video tapes
  • U-matic tapes
  • recordable optical media (CD-R, DVD-R etc.)

Prioritisation must be seen within the wider picture of technological obsolescence however. Many common carrier-based formats, although degrading, will outlast our ability to replay them, and this applies in particular to most magnetic tape-based formats (see section 4). For many, perhaps most archives, obsolescence will pose a more immediate threat to collections than degradation.

Where an archive intends to digitise their audiovisual collection themselves, they are strongly advised to check the quantity and quality of their equipment against the size of their holdings, and to take immediate action to ensure they have sufficient modern equipment and supporting infrastructure to enable the optimal replay of their entire holdings (see section 7).


With one exception, the above list of carriers does not imply an order of priority. Prioritisation within each collection must be based on examination, and will depend on the individual rates of decay of the carriers, the availability of suitable playback 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 program.

Format obsolescence is also associated with a vanishing market for test (calibration) equipment including test tapes, discs and cassettes, as well as ancillary accessories such as empty reels, cassette housings, splicing and leader tapes, etc. Test material is still supported by a few vendors for some sound and film formats.