More from Rebecca Kench on the ongoing conservation of Gustave Doré's 'The Flower Sellers'. You can see the original painting in this post.
'The Flower Sellers' presents us with several unusual problems, the most obvious one can be seen from looking at the back of the painting. The back of the canvas has been coated in a thick layer of wax by a previous conservator in the 1950's. This is not a treatment which we would carry out in this way today, but at the time it was believed that it was the best thing to do for the painting. The wax was melted and applied to the reverse with an iron in the hope that it would go through the canvas to the paint layer and would help the flaking paint adhere to the canvas. However the next problem that we face is what should we do with the wax? When wax is added to a painting in this way it does several things; firstly, it can be reduced but it can never be totally removed from the canvas fibres. Secondly, it prevents the canvas from responding in the usual way to changes in the environment, and thirdly it means that nothing water based can be used on the painting in the future. The second of these problems is the most significant as we think that the thickness of the wax will cause problems at some point. The wax-free canvas fibres will expand and contract dependant on how much moisture is in the air whereas the wax-coated areas will be far less responsive to moisture. This will cause a great deal of stress at the borders of the two areas and eventually you will start to see an outline of where the wax is restricting the canvas from moving when you look at the front of the painting. In most of the deep red paint passage in the centre, in the shawl and around the heads of the two right children, there is wrinkling. Before the wax was ironed into the canvas this must have been sharp and raised and the reason for the wax consolidation campaign.