Cluster analysis to identify microclimate patterns in a multi-room film archive

Inspections of the state of preservation of each film stored in multi-room archives can be time-consuming and expensive. For this reason, the common approach is to perform inspections on films only in rooms selected randomly by the archive curators, that might be not accurately representative of different conservation conditions. This paper presents an objective methodology to select rooms in film archives for inspection, based on their microclimate conditions. A multivariate statistical approach (cluster analysis) was used to objectively identify clusters of rooms with specific microclimate patterns. The proposed methodology was applied on a multi-room archive housing several cellulose acetate films located in the Mediterranean area. The outputs of this work led to a reduction from 26 rooms to 4 clusters representing 4 homogeneous microclimate patterns. These allowed to target specific rooms where to assess the likely occurrence of the vinegar syndrome for cellulose acetate films triggered by thermo-hygrometric storage conditions.