
An experimental program for evaluating the likely behaviour of audiovisual materials in long-term storage or use.
Samples are exposed to various stressors such as elevated temperatures, humidity and pollutants for various time periods and evaluated for mechanical, chemical and signal-carrying properties such as base viscosity, acidity, emulsion melting point and wet strength.
Most programs are very large and require extensive analysis. The following is a short test to estimate shelf life of nitrate film.
To estimate shelf life small samples of nitrate cellulose film are heated to 140° Celsius. The heating accelerates the process of decomposition inherent in nitrate stock. The first stage of decomposition is the giving off of nitrogen dioxide gas.
At a certain point in the forced heating of the film, usually measured in minutes, the samples will have given off enough nitrogen dioxide gas to affect a pH strip. This time is then used to estimate the shelf life of a film before the onset of the decomposition process.
Measured Time | Probable Shelf life |
---|---|
0-25 minutes | 0-6 months |
26-60 | 7-12 |
61-120+ | 12+ |
Compact Discs, CD-Rs and Magneto-Optical Discs are subject to failure by a number of pathways, including photo-chemical decomposition and delamination. The hydrolytic age testing of these discs is the subject of a number of ANSI standards.
The National Film and Sound Archive of Australia acknowledges Australia’s Aboriginal and Torres Strait Islander peoples as the Traditional Custodians of the land on which we work and live and gives respect to their Elders both past and present.