‘Tobias Healing the Blind Tobit’ by Valerio Castello (1650) from the Ferens Art Gallery, Hull. Oil on canvas. This painting was conserved and restored with Art Fund support in 2017.
When the painting arrived at the studio there was a heavy deposit of grey surface dust and dirt on the surface, with various smears and streak marks. The thick natural resin varnish layers which had been applied over the paint layers had now darkened and yellowed significantly. The painting had also been extensively filled and over-painted. The fillings were poorly textured and the retouchings were discoloured and had been applied over original paint layers, as well as extensive paint layer abrasion and loss. The paint layer damage, which is estimated to have affected up to 40% of the painting, was likely to have been caused the painting’s exposure to an environment with elevated and fluctuating relative humidity levels, as well as historic injudicious cleaning methods.
Detail photograph taken during removal of varnish and over-paint layers. The true condition of the damaged original paint layers is revealed on the cleaned right-hand side of the painting.
Detail photograph revealing the extent of ground and paint layer damage and loss. The dark shadows and brown coloured passages of paint were found to be the worst damaged. This may relate to the paint mixture (pigment, binding media and additives) and the painting technique creating a more vulnerable paint surface.
Detail photograph showing the extent of ground and paint layer damage revealed during varnish and over-paint removal. The damage includes ground and paint layer loss which may relate to historic display in an environment with elevated and fluctuating relative humidity levels, as well as paint layer abrasion which was caused by past injudicious cleaning techniques.
After the painting had been cleaned, an isolating varnish was applied to protect the original paint layers, and then the existing fillings were adjusted and textured to imitate the appearance of the surrounding original paint.
The filled losses were retouched with dry pigments bound with a synthetic resin. This was a painstaking process which was carried out intensively over several weeks by a small team of conservators.
The painting was then sprayed with several layers of a non-yellowing synthetic resin varnish.
The reverse of the canvas was dusty and dirty. A number of the expansion keys were either missing or inadequate, and not securely attached to the stretcher.
Dust and debris was cleared from the reverse of the canvas using a conservation sponge and small hand-held vacuum cleaner. The old expansion keys were replaced where necessary, with new beechwood keys, and secured to the stretcher using monofilament line, brass screws and cups. This will prevent the keys from falling out of the stretcher, becoming lodged between the lower stretcher-bar and canvas, and causing a bulge distortion at the front of the painting.