A non-destructive approach to the study of 20th century gelatine negatives

Abstract

Two 20th century gelatine glass plate negatives, belonging to Eduardo Nogueira’s collection owned by the Photographic Archive of Évora, were studied by an in-situ multi-analytical approach that included technical photography, optical microscopy, scanning electron microscopy coupled with X-ray microanalysis and micro-FT-IR spectroscopy. The plates present several damages, probably due to neglected handling, and to tempera-ture and humidity fluctuations in poor storage conditions. Silver sulphide and silver chloride compounds were detected on silver mirroring present on both plates. Fungal colonization was also observed on both plates. The use of gelatine emulsion was confirmed and in the case of N2 a cellulose based resin, probably mixed with oil, was used over the emulsion to create a rough surface for the use of graphite to enhance the image.