Using fluorochromised gelatine to visualise the sealing effect of cyclododecane during re-adhesion of flaking paint on canvas
University of Cambridge Museums
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Soppa, K. (2018). Using fluorochromised gelatine to visualise the sealing effect of cyclododecane during re-adhesion of flaking paint on canvas. https://doi.org/10.17863/CAM.34061
This paper is published in the book ‘Subliming Surfaces: Volatile Binding Media in Heritage Conservation’, ed. Christina Rozeik (University of Cambridge Museums, 2018), pp. 53-64.
When working with low viscosity adhesives on canvases without a sizing layer, it is advisable to mask the canvas prior to consolidation (for example with CDD solutions). The use of fluorochrome-labelled gelatine (type A, 180 Bloom 5% w/w in distilled water) in combination with fluorescence microscopy allows the sealing effect of various methods of cyclododecane (CDD) application to be visualised, in order to optimise the techniques for re-adhesion of flaking paint on canvas. As solvents for CDD, petroleum ether (boiling point <40 °C) and white spirit (b.p. 100–140 °C) have delivered positive results. The observed adhesion was best when using CDD in petroleum ether <40 °C. However, from a practical point of view, the handling of CDD in white spirit 100–140 °C is easier, the penetration is laterally wider and therefore the sublimation faster. Application of solid CDD either as chips or with a spray can (both worked in using a heated spatula on the reverse of the canvas) produced irregular and poorly reproducible results. There is a significant difference between the two CDD application techniques: if the paint has no contact with the canvas, the CDD solution stops at the canvas interface, whereas melts can penetrate further, embedding the fibres entirely and even filling the joints – or they do not reach the interface. A further important practical observation is that there should be no contact with the reverse of the canvas during application of the adhesive since this contact increases capillary forces, allowing the adhesive to penetrate more easily towards the other side. An open- celled foam, which is rigid enough for placing weights on the painting after application of the adhesive, proved to work well as an underlying support.
This record's DOI: https://doi.org/10.17863/CAM.34061
This record's URL: https://www.repository.cam.ac.uk/handle/1810/286754