Varnish

When a painting is cleaned, two things are typically removed from its surface. The first is any accumulated surface grime. This can be anything from cigarette smoke, mud, cooking oils, or bug trails. Anything that mucks up the surface of the painting shouldn’t be there, but has accumulated over time because the painting was near them. Second is the varnish.

Varnish is a thick, typically clear liquid material. It is made from a mix of natural resins and solvents (like turpentine). They function as sealants for paintings, protecting them from that surface grime, locking down all the layers of paint, and saturating those layers to look more vibrant and cohesive. The color change is discussed below, but first, why does varnish need to be removed if it does all these really great things?

Over time, all natural resins will change. This is inevitable, and part of having a work of art interact with the natural world. Resins will react to light, weather, and other natural changes over time, and become discolored and ugly. They can stain, often darkening to a yellow or gray. They can crack, leaving wide breaks in the artist’s work. They can even become milky or cloudy, leaving patches of weirdly colored paint in weird spots. All that and more, and all just because people wanted to keep their art in a place they could see it!

So the material kept over that finished painting has aged and changed and is potentially doing harm to the work beneath it by bending and changing in this way. This is when more conservators decide to clean the varnish off of a piece.

If it is deemed in poor enough condition, conservators take to removing this layer from the painting so that it can be spotless, restored, repainted, and then sealed again with a new varnish. This process is tricky and comes with both a high risk and a high reward. On the one hand, if all goes well the painting will be free for the conservator to touch up any damages, and then with a new and unstained varnish, the piece will look as beautiful as it did the day the original artists applied that first varnish. It could potentially mean looking at the painting in a whole new way, a way the artist intended. On the other hand, each time the varnish is removed, it risks causing damage to the original paint layers too. Varnish that hasn’t been applied as part of conservation is often made out of the same general materials that make up the paint underneath it. This is especially true for older paintings, when synthetic varnishes didn’t exist yet, and so they were definitely all the same material. That means that the chemical abrasions that are removing the varnish are also potentially removing the paint underneath it.

Because of that, it’s important to understand the chemical composition of the varnish. Understanding its make allows for a cleaner cleaning, and potentially allows conservators to make a special varnish-antidote, which could knock off just that top layer and leave the paint mostly unharmed. The lab work is an extremely useful tool for any conservator and allows for more specificity, accuracy, and care when making such dramatic changes. After that, the varnish removal should happen slowly and carefully. Most conservators use small Q-tips or cotton swabs dipped in the varnish-antidote to then softly clean up that top surface. This process takes time but ultimately allows the conservator the most amount of control and precision in their work. In the end, with all the varnish removed, the painting looks something like this:

Here it is clear how the varnish being removed meant more of the breaks and damages became apparent. Some of those cracks were already there, either filled in by other conservators or the artists themselves, but others were due to the inherently invasive process of removing that top layer. The color is also much duller than the original piece, not unsaturated without the unifying layer on top of it to control those colors and make them darker and lighter respectively. Once the painting has been fully restored and re-painted with a new varnish, you can see how much cleaner, brighter, and more colorful this piece is. The new varnish clarifies and enriches the painting, and hopefully makes it look closer to its original artist’s version.

This varnishing process is shown in action in this video here: