Before magnetic tapes came into general use, recordings were made on so called ‘instantaneous records’, which could be replayed immediately after the cut. The most popular form was the ‘lacquer disk’, or ‘acetate disk’ used from the 1930s to the 1950s in broadcasting and scientific institutions for unique recordings. Chemical decomposition (hydrolysis) causes the information carrying lacquer layer to become brittle and thus to separate from the metal or glass core of the record. >> More