3. 12. 2014, 6pm, Emma Richardson, UCL, Department of History of Art: CA Dreaming? The Nightmare of Cellulose Acetate Artefacts

Venue: UCL, Department of History of Art, Gordon Square no. 20, London WC1E6BT, room 3/4

Talk by Dr Emma Richardson (UCL, Department of History of Art): Synthetic and semi-synthetic polymers comprise an increasing portion of cultural heritage and archival collections. The growth in polymer manufacturing and engineering that occurred throughout the twentieth century inevitably led to many artists and designers employing these new and relatively inexpensive materials in their works. However, the physical instability of some polymer formulations now pose particular problems for the heritage profession, where longevity and conservation is of primary importance. One such example is the case of cellulose acetate film, which was used extensively as the substrate for animation art works. Owing to its transparency and flexibility, cellulose acetate film was employed as the base material for animation cels between the 1920’s and early 2000’s, with the animation painted in reverse, the image being viewed from the opposite side to the paint layer. Over time many of these films have been found to lose their mechanical integrity, which impacts on the handling and display of the cels.

The primary properties of interest with such works of art are those related to the flexibility of the sheet material and shrinkage mechanisms. As with all archival material and art works, the physical nature of an animation cel will impact on its access for both research and display. Limiting the handling of vulnerable material helps to mitigate damage. However, determining the condition of an object can be challenging, especially when the point at which change is visible to the eye usually means that the object is already heavily degraded. Further issues arise where aesthetic or ethical considerations limit sampling of an artefact, preventing bulk analysis and assessment of an object’s physical integrity. In such cases assessment often needs to be made through correlations between microanalytical methods and the bulk properties of surrogate materials.

The work presented will focus on the deterioration characteristics of cellulose ester films, with particular attention given to the correlations between micromechanical and thermal properties of degraded film and non-destructive analytical techniques. It will be demonstrated that the higher the plasticizer content the greater the ability to strain harden, and therefore the least vulnerable to mechanical damage from archival handling. The correlation between the critical plasticizer content, as determined by non-invasive and micro-invasive techniques, and the working properties of cellulose acetate film provides a means of assessing stability, and highlights artefacts at risk from physical damage.