Les négatifs photographiques en nitrate de cellulose : le...

Notes: Texto en francés, resumen en inglés
Sumario: Since 2002, a preservation and hazard prevention plan is undertaken under the supervision of Atelier de restauration et de conservation des photographies (ARCP) regarding the cellulose nitrate negatives in the photographic collections of the City of Paris. Approximately one million nitrate negatives are dispersed among four millions negatives on all supports, and belong to 13 institutions (archives, museums, libraries, as well as one photographic agency). The mass of nitrate in two establishments exceed 50 kilos, the weight from which the French legislation prescribes very restricting laws for the storage of cellulose nitrate materials. This article first proposes an outline of the safety issues associated with cellulose nitrate, followed by a summary of the legal background and norms that apply to this material. The second part presents the method elected by the City of Paris to solve this problem, while the surveys of the collections are completed and negatives are prepared to move into new storage areas. A storage solution including all collections was chosen. It was, given the strictness of the law, the only satisfactory answer to ensure the safety as well as the preservation of the negatives. Because some collections require daily access for commercial purposes, two storage areas are planned. One area will be optimized for short term storage, with climate conditions of 14ºC and 30-40% relative humidity (HR). It should warrant accessibility of the collections for exploitation in an adjacent works-pace, and allow conservation and digitization works to be carried out. The second area at 2ºC and 30% RH will be used for the digitized collections, or those not exploitable, for long term storage at low temperature. This nitrate plan turned out also to be an opportunity to know better the photographic collections of the City of Paris, and to achieve a big step in their preservation.