Fungal colonisation and contamination of cinematographic film: a threat to film and archivists

Bingley, Gavin David (2012) Fungal colonisation and contamination of cinematographic film: a threat to film and archivists. Doctoral thesis (PhD), Manchester Metropolitan University.

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Abstract

Film archivists have expressed concern regarding the aerial release of fungal spores during inspection of mouldy cinematographic film. The aim of this study was to investigate this and identify of the contaminants causing this concern, and then to make recommendations to archivists regarding safe handling of such film. Eighteen films donated to the North West Film Archive, in Manchester, UK, were examined. During a simulated inspection procedure, spore release ranged from zero to several thousand spores per m3 (i.e. above numbers considered 'safe'), with films that were the most visibly mouldy usually yielding the highest numbers of colonies. Predominant contaminants were Aspergillus and Penicillium. A. versicolor was the most common species isolated (8/15 isolates identified by CABI), and gelatinase assays indicated that this was also the most gelatinolytic species, perhaps explaining its high frequency of isolation, and indicating risk to film. No overtly pathogenic species were isolated, so the risk to archivists may be considered low. Thus, informed recommendations for safe handling could be made. Wiping of lightly contaminated reels may remove superficial surface mould growth but cleaning of heavily contaminated reels is not recommended, because hyphal growth is likely to have penetrated the gelatine emulsion layer. In addition, high numbers of spores released could pose a health risk to archivists. Although the contamination of some film was no longer viable, actively growing mould may cause further deterioration if reels are not stored in conditions not favourable to growth. Currently, assessment of viability is by culture, a method not usually available to archivists. An alternative method was explored by analysing microbial volatile organic compounds (MVOCs) released from fungi isolated from mouldy reels, using headspace solid phase micro-extraction (SPME) coupled with gas chromatography–mass spectrometry (GC-MS), to determine whether any compounds were common to isolates. Over 150 volatile compounds were detected from 16 fungal isolates, with 3 VOCs being the most common: 1-octen-3ol from 13 isolates, 3-octanone from 10 of the isolates and 3- octanol from 4 isolates. These three key chemical markers are indicative of viable fungal growth on cinematographic film, thus their detection would preclude the need for traditional microbiology laboratory culture methods. Development of 'one-shot ' screen printed sensors coupled with a hand held device proved possible, enabling in-can indication of viable mould, thus enabling films to be stored appropriately to halt further growth. This study broadened the knowledge of contaminated cinematographic film in the hope that more valuable archive footage can be preserved.