Acetates
Acetates—more accurately described as lacquer discs—were individually cut on a recording lathe rather than pressed from production stampers. The recorded surface generally consisted of a thin lacquer coating applied to a rigid metal base, most commonly aluminium. Despite the familiar name, the recording surface was not usually made from acetate.
An acetate could be produced directly from a tape and played immediately, without the plating and pressing processes required to manufacture a conventional record. This made acetates useful for evaluating a recording, checking a disc cut, approving proposed content or supplying a reference copy before the finished record became available. Copies could be heard by record-company personnel, artists, producers or management.
Unlike a vinyl pressing, each acetate was cut separately and was not intended for repeated use. Its comparatively soft surface wore quickly, while the lacquer could shrink, crack or separate from its metal base as it aged. Surviving examples must therefore be handled and played with particular care.
EMI (Australia) acetates were commonly pressed with plain 'DIRECT RECORDING' labels on which details such as the artist, title, matrix number and speed were typed or handwritten. Because their contents could differ from the subsequently released record, surviving acetates sometimes preserve alternate mixes, edits, running orders or other pre-release variations.
