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gent acid smell and the brittleness, buckling, and shrinkage of the negatives, vinegar syndrome affects all types and formats of acetate film, as illustrated by an example from the Corbis collection (Figure 65). The historical collections purchased by Corbis consisted predominantly of cellulose acetate and polyester film. The cellulose nitrate film in the collection, when not previously discarded, also showed obvious signs of decay, including yellowing of the support, silver mirroring of dark areas in the image, and softening of the gelatine binder (Figure 66). In addition, parts of the colour images on polyester film included in the UPI collection had begun to fade because of the unstable nature of the colour dyes, rendering these images unusable. Handwritten remarks on a colour negative from the Bettmann collection reflect this degradation: “Poor quality, no hope, no original prints, no high quality dupes on file, no options.” (Figure 67) In addition to the photographic material itself, envelopes, negative sleeves, markers and stickers, folders, caption sheets, index cards, and registers – all indispensable sources for the exploitation and interpretation of the visual material – were also prone to deterioration.
Figure 65: Corbis Film Preservation Facility, Deterioration process of cellulose acetate film, 2009.