Cleaning tests for fellow conservators
With the New Cleaning Methods and The Modular Cleaning Program (MCP)
Our fellow conservators regularly approach Marjan de Visser to advise how best to clean a painter. This concerns not only paintings but also wall paintings. Of course, also painted furniture. This not only involves dirt, but also varnish.
Method of cleaning tests
After all, two conservators see and know more than one. An exciting challenge is to understand a problem as well as possible and to find the best solution through tests. Marjan de Visser performs tests based on The Modular Cleaning Program. Of course, this does not only apply to the restoration of paintings. So also suitable for wall paintings, furniture, and interior restoration.
The most recent examples of cleaning tests for colleagues:
A seventeenth-century gentleman’s portrait appeared to be covered with a gray/gray haze after the varnish had been removed. Under the microscope at 400x magnification, it can be seen that the surface is very rough.
But what is this rough layer that absorbs the light and covers the paint stroke? Because the deep tones of the black suit are not visible at all. Instead, we see a shapeless gray. Could this haze be the residue of a previously used cleaning agent? Maybe it is a matter that comes out of the paint layer. Possibly it is the beeswax from the wax & resin covering. Remember that the caused by fungi. Because the painting hung for a long time in an unheated room against an outside wall. We will conduct cleaning tests based on these questions.
To measure the surface acidity:
The acidity of this painting is pH 7.0.
The tests I perform on it are:
1) buffer pH 6.5 result: +
2) buffer pH 8.5 result: ++
3) buffer pH 8.5 with citric acid result: +++
4) buffer pH 8.5 with EDTA result: ++
5) Pemulen buffer pH 8.5 with citric acid result: +++
6) Pemulen buffer pH 8.5 with citric acid – 5% D40 result: +++
7) Pemulen buffer pH 8.5 with citric acid – 5% D40 + 5% A100 result: +++
Other examples of cleaning tests for fellow conservators are:
A Dutch lacquer cabinet for Michiel de Vlam in 2017,
An early seascape by Vincent van Gogh for the Van Gogh Museum in 2017
The third-class waiting room at Haarlem station for Judith Bohan in 2011
