Assessing a disc collection, the French National Library's 78 RPM disc collection

The French National Library is hosting a research programme focusing on preserving audiovisual and multimedia documents. The results should help to define the preservation policy and the priorities of digitization of the Audiovisual Department. Since 2007, this programme has been focusing on the chemical composition and degradation of 78-rpm records. These discs, considered to be “stable”, are in fact little understood and there are no guarantees as to their long-term preservation. The research was initially restricted to the homogeneous 78-rpm discs, manufactured during the period 1900-1924. The work consisted of a review of the literature, to find “recipes” or registers of raw materials used for the manufacturing of 78 rpm discs. Physicochemical analyses of original discs were performed to confirm the data found in literature. Since 2010, the research programme has been extended to the heterogeneous 78-rpm discs, manufactured after 1924. In the frame of the programme, a statistical survey of our whole collection (more than 250,000 items) was undertaken in order to assess its degradation state: determination of degradation patterns and evaluation of their frequency. The final step is to understand the degradation process, compiling metadata, analysing the composition of the discs and trying to determine correlations between both. My presentation will focus on the statistical survey.