Historic Churches 2018

BCD SPECIAL REPORT ON HISTORIC CHURCHES 25 TH ANNUAL EDITION 31 Although cleaning is one of the most irreversible treatments that conservators embark upon, it is usually deemed to be a necessary part of most conservation programmes. In this instance the surface dirt and varnish were contributing to an overall darkening of the images and a shift in hue and tone of the applied colours. Part of the assessment responsibility is to adhere to conservation principles and consider the artistic intentions, purpose and context of the artworks. Considering the importance of colour in the chancel paintings and the need for clarity of form in depicting the scenes, the decision was taken to remove both the surface dirt and varnish to reveal the colours originally intended. During the testing phase and the ‘unpacking’ of the layers it was found that the accumulated dust and pollutants on the surface could be successfully separated from the varnish layer and removed using aqueous cleaning methods, and that a formulated solvent-based method could be used to gradually remove the degraded varnish. The removal method was based on a swab application of propanone placed within a gel formulation (using Ethomeen and Carbopol, the process developed by Richard Wolbers to help maintain contact between the solvent and the surface, while minimising evaporation). In this case the gel was applied by swab and rolled on to the surface as if it were a free liquid solvent. The discolouration on the swab was monitored during cleaning and the gel was then removed from the surface with a clean cotton swab and water. This method proved to be both effective and safe, enabling the discoloured varnish to be separated from the paint layer. The abraded sections of the original gold were re-applied using oil size and 24 carat gold leaf. The colour disparity between the new and aged gold was corrected by the application of toned transparent glazes over the new applied gold. These glazes were mixed using pigments bound in Paraloid B72 resin. All the materials and techniques were selected according to our guiding conservation principles with the long- term vitality of the panels in mind. Two of the most important ethics, the reversibility of treatments, and adhering as far as possible to the original intentions of the artist, were observed at all times. The photographs are testimony to the dramatic improvement in the appearance of the panels. Dull greys turned into brilliant whites, browns into rich reds and the gilded surfaces reflected light with the brilliance of freshly applied gold leaf. References and further information I Horovitz, “Paintings on copper: a brief overview of their conception, creation and conservation”, Proceedings from the symposium, Paintings on copper: and other metal plates: production, degradation and conservation issues , 17–26, València, 2017 L Pavlopoulou, “Chemical, physical and mechanical decay processes in oil painted copper objects”, Proceedings from the symposium, Paintings on copper: and other metal plates: production, degradation and conservation issues , 43–54, València 2017 D Everingham, “The characterisation, origin and treatment of ‘surface eruptions’ on a seventeenth century oil on copper”, MA Dissertation , University of Northumbria, 1998 Phoenix Art Museum, Nelson-Atkins Museum of Art, and Mauritshuis (Hague, Netherlands), Copper as canvas: two centuries of masterpiece paintings on copper , 1575–1775 . New York: Oxford University Press, 1999 MICHAEL BOWES (michaelbowes99@ gmail.com) studied for his MA Conservation of Fine Art at Northumbria University. After working at The Bowes Museum in County Durham and a short internship at the V&A Museum he is now Assistant Paintings Conservator at David Everingham Conservation Ltd in Harrogate, North Yorkshire (www. everinghamconservation.co.uk) . Before conservation: opaque white blanching of the varnish obscured significant areas of the oil on copper paintings. An angel from the Adoration of the Magi, partly cleaned to show the discolouration caused by the layer of surface dust and dirt, and the yellowing of the varnish layer.