The Cosmetic Phase

Part 11 of Conserving a Canaletto

The idea of reversibility is a very important concept in modern conservation practice. I chose materials with good and known aging characteristics, understanding that my work may need to be removed and/or redone, in the future. It is important that my conservation treatments are reversible. I know that the adhesive I chose to bond the original and lining canvases could be separated in the future and will not cause further harm to the artwork. I also made choices about the materials used to reintegrate damages and developed layered systems that allowed me to work freely but ensured the safety of the original surface.

Before I could begin the final treatment phase, cosmetic integration, I first had to isolate the paint surface from any of my cosmetic work. I did this by brushing a thin layer of varnish on the surface to not just isolate my work from the original, but to also saturate the surface slightly (like a varnish should), which allowed me to more accurately color match during the in-painting phase. The varnish I chose was a synthetic resin whose aging characteristics are well understood and will not turn yellow over time like the natural resin varnish I just removed. And of course, should the picture need to be cleaned in the future, the varnish can be safely removed.


The first step of the final treatment phase called cosmetic integration is filling. All of the areas on the canvas where paint flaked off, called losses, needed to be filled, leveled, and textured prior to any cosmetic compensation. Without proper filling, all of the losses would remain visible and the viewer’s eye would be drawn to them, not the painting as a whole composition as Canaletto intended. I used a very fine calcium carbonate-based filler with a synthetic media, which created when dry, a very fine, porcelain-like surface. And again, I know that it can be safely removed in the future should the need arise.


The next restorative phase is color-matching, where I re-integrated damages back into the picture. The process is called in-painting because, unlike the previous restorer, I applied color only to damaged or disfigured passages of the picture, not to enhance or add to the original. The goal of this phase is to make the damages disappear so that the viewer can enjoy the entire picture without focusing on the damages. Unlike previous restorers, I didn't use oil paints, but pigments that were ground in a synthetic resin of my choosing based on multiple factors such as its aging characteristics, solubility, and gloss so as to match the reflectance of the original surface. The solubility of the in-painting media differs from that of the isolating varnish, so if I should need to remove my in-painted passages, I can do so without disturbing the isolating varnish. Indeed, a future conservator armed with the knowledge of what materials I used, will also be able to successfully remove my cosmetic work without even touching the original.

A final varnish, reframing, and the treatment is complete! I will be publishing another post about conserving the frame soon.

James Squires was the paintings conservator at the Denver Art Museum.