National Film and Sound Archive of Australia (Australia)
Under prolonged storage motion picture film may adhere within the reel forming a solid mass, this is referred to as blocking. Films in this condition may not be unwound without significant damage. The damage may range from changes in the surface of the emulsion through to tearing and destruction of the film.
Blocking has been a research challenge at the National Film & Sound Archive of Australia (NFSA) and our research has identified three primary types of film blocking:
- Gelatin cross linking between layers
- Exuded additive chemicals forming a cementing layer
- Decomposition by-products forming a cementing layer
In response we have developed a series of conservation treatments to deal with each of the mechanisms of blocking. The success rate of these treatments is very encouraging and NFSA has conducted several projects to treat large numbers of affected films.
This paper will briefly outline the causes of each type of blocking, the research we have done into each condition, details of the treatments we have developed, case studies of treatments and the risks involved in the treatments.
Mick Newnham is currently the Manager of Conservation & Research, at the National Film and Sound Archive of Australia (NFSA) based in Canberra, Australia. At the NFSA Mick manages three conservation laboratories, a paper and objects laboratory, a specialist audiovisual objects laboratory and a photographic laboratory. In his role as a researcher Mick engages in original research on issues surrounding the conservation and long-term preservation of audiovisual media such as film, magnetic tape and optical discs. This research has been widely published and has been incorporated into preservation practices and commercial products across the world.