chapter  8
The future of plastics conservation
Pages 8

Potential degradation markers for video and audio tapes, which contain polyester and polyurethane, have been investigated recently as part of the Presto Space project ( Thiebaut et al., 2006 ). Chemical markers investigated included pH of the tapes ’ surfaces, which was expected to fall with the onset of hydrolysis, while mechanical markers included the loss of cohesion between the various materials which comprise tapes. Because few cultural institutions and private collectors have access to analytical instruments, effective degradation markers should be based on readily detectable properties such as colour

change or colour change induced in another material, and the evolution of volatiles which results in odour or change in acidity.