A Systemic Approach to the Preservation of Audio Documents: Methodology and Software Tools

Table 1

Typologies of analogue mechanical carriers.

Carrier	Period	Composition	Stocks
Cylinder recordable	1886–1950s	Wax	300,000
Cylinder replicated	1902–1929	Wax and Nitrocellulose with plaster; (blue amberol)	1,500,000
Coarse groove disc replicated	1887–1960	Mineral powders bound by organic binder (shellac)	10,000,000
Coarse and microgroove discs recordable (“instantaneous discs”)	1930–1950s	Acetate or nitrate cellulose coating on aluminum (or glass, steel, card)	3,000,000
Microgroove disc (vinyl) replicated	1948–today	Polyvinyl chloride-polyacetate copolymer	30,000,000