Characterisation and removal of degraded surface coatings - A case study

Abstract

This study investigates the characterisation and removal of a degraded surface coating on an eighteenth-century flower still life painting of unknown provenance, currently held in a private Swedish collection. Visual and ultraviolet examination revealed an uneven varnish layer, which was compromising the legibility of the composition. FTIR analysis of an extracted varnish sample indicated the presence of mastic resin, guiding the systematic selection of an effective solvent system using the TriSolv software program. Two gel-based delivery methods and Evolon® CR microfilament cloth were evaluated as alternative approaches to solvent delivery. Agar gel in both aqueous and fully ethanol-exchanged formulations proved ineffective for varnish removal on this painting and caused surface blanching. Evolon® CR demonstrated the most effective and controlled varnish removal across all the application methods tested, with no damaging effects on the paint layer observed.