Glass slides that require special attention, such as those with lifting emulsion layers, are stored in custom-made boxes to prevent further damage from occurring during handling.
The accessioned glass slides are stored in the same controlled environment as the rest of the document collection. The temperature and relative humidity are set at 18 degrees Celsius (± 2 degrees Celsius) and 40 per cent RH (± 5 per cent). These conditions are at the top end of, but still within, the range recommended for glass plate negatives by ISO 18918: Imaging materials – Processed photographic plates – Storage practices . Stability in environmental conditions is important for photographic emulsions on glass. Consequently, temperatures in the NFSA storage vaults rarely fluctuate, even within the full deflection of the set point range.
The NFSA’s glass slide project is ensuring that over 10,000 historically significant slides in our collection are preserved under controlled conditions for future generations.
As work progresses on digital preservation, copies of these slides are uploaded to our online collection database, providing virtual visitors across the globe with access to Australia’s audiovisual heritage.
This is the third part in a three-part series. Read Part one and Part two.
A version of this article was presented at the Australian Institute for the Conservation of Cultural Material (AICCM) conference in Melbourne, in 2010.