Gramophone discs developed in the late 19th Century became the dominant form of domestic audio in the 20th Century. There are three main disc types; shellac based, (78s); acetate coated metal or glass transcription discs and vinyl long-play, (LP) discs. During the second half of the 20th Century virtually all gramophone discs were Vinyl LPs and seven inch'45s'. Technically, the discs have a single modulated groove that generally spirals from the edge of the disc to the centre. The encoded information in the groove is reproduced using a stylus and amplification. Digital compact discs were commercially introduced in the early 1980s and signalled the beginning of digital audio in the home. Despite the current predominance of digital recording and reproduction, vinyl discs have been resurgent in the past decade or so and are, along with analogue turntables, still commercially available.
Composition of discs
All materials degrade over time. We cannot control this inevitable deterioration, but we can control how fast it happens. Certain materials are susceptible to deterioration in particular ways just because of their properties, and other materials deteriorate as a result of particular environmental conditions.
- Shellac discs are relatively brittle and can shatter if dropped. The use of heavy steel stylii to reproduce the recorded sound caused rapid disc groove wear.
- Instantaneous recording discs consist of a very thin layer of cellulose nitrate or acetate over a metal substrate. As the plastic degrades, it shrinks, causing cracking of this layer. This makes the disc unplayable.
- The PVC/PVA copolymer used for vinyl discs includes stabilising compounds that has given them a relatively long useful life. The mechanical reproduction with a stylus also causes wear over time. Vinyl discs will readily buckle if exposed to heat or sunlight.
Preservation and storage
Gramophone discs should last as long as required with careful handling and storage:
- Handle the disc by the edges and central label only.
- Use clean hands and disposable nitrile gloves
- Use the correct equipment when playing gramophone discs, to prolong their useable life. The disc should be clean and free from dust before playing. The stylus should be in good condition and set at the correct weight, (3g – 7g).
- When not in use, discs should be stored in a protective sleeve that excludes dust and dirt.
- Archival quality materials should always be used when packaging archival records.
- If packaging a broken disc, make sure the edges of the disc do not touch as movement can cause further damage. Do not discard any pieces and ensure that they are kept together. This is particularly important for 'acetate' discs that have flaking coatings.
- Do not apply labels directly to gramophone discs. Label the protective sleeve with any additional necessary identifying information.
- Make sure the box is not too big or too small, and the box is not too full or too empty, as both instances can cause damage.
- Gramophone discs should be stored upright on shelves.
- Boxes or shelf dividers should provide support so that the discs do not lean over at an angle while on the shelves.
- Because shellac discs are brittle store them on static rather than mobile shelving to reduce the chance of them falling from the shelf.
- Ensure that the disc is clean, free of dust, unaffected by mould or active corrosion, before placing it in protective packaging. If affected items are identified, then isolate them and seek preservation advice through the Agency Service Centre.
The National Archives provides a Standard for the Physical Storage of Commonwealth Records (pdf, 326kb) that recommends suitable environmental conditions for gramophone discs.
Lights should be turned off whenever possible. Storage areas should not have windows, but if they do they should be covered with curtains or blinds.
Cleanliness is very important in storage areas to protect records and for work health and safety. Never allow food or drink to be taken into a records storage area, and ensure the area is cleaned regularly. Insects and rodents, once attracted to a records storage area by food, may begin to eat the records. For further information the National Archives provides information on Integrated Pest Management.
Storage equipment should be designed and set out to minimise damage to any items that are stored within it:
- Store items off the floor in case of flood. Plinths or pallets may be used to do this if the item will not fit into shelving.
- Equipment should be made of coated metal. Wooden shelving should be avoided, as it can release harmful vapours, contribute to the spread of fire and may harbour insects.
- Items should not be stored on the top of shelving as they may be too close to ceiling lights and there is also the possibility of water damage from fire sprinklers.
- Aisles between equipment should allow easy access to and removal of items.
- Suitably sized tables should be located next to the storage cabinets; this will provide a place for staff to comfortably and safely check the contents of boxes and drawers and retrieve individual items.
- Gramophone discs, particularly non-commercial and transcription discs can contain unique information content that should be preserved. Copying to an uncompressed digital format is an important conservation and access process. Discs should be copied by a skilled professional on high quality equipment. Please contact your local National Archives of Australia office if you are considering copying your gramophone discs for preservation reasons.
Contact the Agency Service Centre.