Week Two: Solubility tests

Hi. Welcome back. Last week I finished my second week of work, and let me tell you what I did. The paint layer on this painting is, most likely, egg tempera. Once the egg tempera paint has been applied, it dries and becomes insoluble in water. The type of varnish present on the surface of this painting is thought to be composed of a natural resin. In order to remove the discolored layer of varnish safely, different organic solvents were tested on a very small area by gently rolling a cotton swab. The effects of the solvents on the varnish and paint layer were carefully studied under the microscope. Of course, we want to use a solvent that is able to remove the varnish layer but that leaves the paint layer unaffected.
	Here you can see some solubility tests showing that the solvent on the left, left the varnish layer unaffected, whereas the solvents on the middle and on the right, were able to dissolve varnish layer.
Last week I started cleaning the white areas on the figure of the Bishop.
	Here you can see that on the right, the varnish layer has been removed. Notice how much the varnish layer has yellowed, masking the original colors. Old repaints that were done in a past restoration in the 70s are removed at the same time.
	By removing the varnish layer and the old repaints, the fine original brushstrokes of paint can be appreciated again. However, the real condition of the paint layer is also revealed, showing a very abraded surface. Unfortunately, this is the case with many old paintings that have suffered past abrasive cleaning campaigns that removed some of the original paint.
Come back soon to follow the progress on the varnish removal.

Page 3 of 9 | On the next page: Week Three: Old Repaints