Phonogrammarciv Austrian Academy of Sciences (Austria)
One of the most urgent preservation issues in audio-visual archiving is the decay of material based on cellulose acetate. The chemical deterioration process called vinegar syndrome is a widely investigated topic that is feared as a chemical reaction causing molecular chain scission, thereby degrading audio-visual media with a base of cellulose acetate. However, furthermore it seems that a second chemical deterioration process of plasticizer loss has been so far underestimated in the world of audio-visual archiving.
Based on such comprehension, together with the leading Austrian research institutions, a method to permanently refresh brittle acetate media has been developed and will be available for audio tapes and also cinematographic film material. The treatment is designed to (re-)gain material elasticity and therefore playability, enhance the digitisation process and quality due to higher physical flexibility of the material, reduce acidity in the material, refresh the carrier material in the sense of playability and long-time storability and optimise storage conditions in the long time.
The paper briefly describes the mechanisms of acetate degradation as well as related ageing phenomena in audio-visual carrier materials, focusing on some not so well known facts about the chemical deterioration processes involved. Possible solutions are discussed and the recently developed restoration and preservation process is outlined, as well as various methods to verify the restoration success. Finally results are presented, covering successfully restored audio as well as motion picture film.
Nadja Wallaszkovits studied musicology and audio engineering in Vienna and has been working as sound engineer for national and international recording companies. In 1998 she joined the Phonogrammarchiv where she manages the audio department as a specialist for audio restoration, rerecording and digital archiving. She is consultant for archival technology for national and international institutions and is guest lecturer at the University of Vienna and at the Universities of Applied Sciences in Berlin and Berne.
Recently she took over the management of the new research department of NOA GmbH, a Public Private Partnership collaboration dedicated to the restoration of acetate media.
Nadja Wallaszkovits is vice chair of the IASA Technical and Training & Education Committees, and is member of the AES Technical Committee.