Collaborative PhD Student
Courtauld Institute of Art, UCL and Scuola universitaria professionale della Svizzera Italiana (SUPSI)
Professor Sharon Cather, Dr Emma Richardson and Professor Fracesca Piquè
Readhesion interventions on wall paintings: assessment of penetration, deposition and bond strength of organic, water-based adhesives on lime-based secondary supports
Adhesion failure of paint and preparatory layers is typically addressed by attempts to readhere the lifted layers. Bonding mechanisms between paint, preparatory layers and their support and are complicated, as are reasons for their failure. Although bonding mechanisms are thoroughly explored within the adhesives industry, they remain poorly understood when applied to the complexity of wall painting conservation. The properties of adhesive materials used in this type of intervention have been evaluated in a number of studies, however the physico-chemical interactions between paint and preparatory layers, their support, and the applied adhesive, remain poorly understood. When addressing adhesion failure, selection of a suitable adhesive material needs to consider not only the properties of the material, but also the dynamics involved in the adhesion process. Research on bonding mechanisms is extremely important in order to clarify the causes behind failure of adhesion. Understanding these mechanisms would help define specific parameters that need to be considered when tackling evaluation of the intervention. In wall painting conservation, difficulties often arise in evaluating conservation treatments. Not only are there inevitable constraints when planning in-situ non-invasive assessment, but also test methodologies designed for the adhesive industry for evaluating strong adhesives are often not appropriate for far weaker adhesive systems. Comparison of high- and low-tech methods that are accessible to the independent conservator, would be highly desirable to provide tools for the design of specific readhesion interventions and accessible evaluation methodologies.