Removing varnish from an oil painting
Removing varnish from an oil painting is a very delicate operation. When the restorer Marjan de Visser decides to start removing varnish from a painting, she first studies the varnish. This is performed in daylight and under UV fluorescentie.. As the color of the fluorescence by the varnish tells more about the type of varnish that is used. The varnish is then tested for solubility. Because a droplet of a certain solvent provides a lot of information about the further research. Measuring the acidity of the varnish also helps in the research for a suitable cleaning agent. Of course, the choice of a matching technique is also important. One of the methods that the paintings restorer can use in the restoration workshop is The Modular Cleaning Program. When you want to know more please read articles on conservation by Marjan de Visser.
Examples of yellowed and aged varnish
Varnishes made from natural resins like Damar and Mastic become yellow by age due to oxidation. This aging phenomenon is clearly visible in a painting from the 18th century. Here the restorer Marjan de Visser found a dark yellow varnish. However, the varnish had not only darkened, but also cracked and therefore it resembles a snake skin. The performed varnish removal tests were surprising!
varnish removal using a solvent gel
One of the features in The Modular Cleaning Program is the use of gels and emulsions. There are water based gels like Xantan, Pemulen an Methyl Cellulose but also solvent gels. These organic solvent gels are prepared using Carbopol and Ethomeen. Carbopol is a huge polymere that can grab the solvent. These gels are one of the options for removing varnish form an oil painting.