View Full Version : A Sound but Relatively Obscure Practice with Acrylics

12-18-2009, 07:42 PM
This seemed to be worth sharing: it seems to be a relatively little-known aspect of working with acrylics.

There are ingredients (soap-like compounds) in artists' acrylic paints and mediums that slowly migrate (over the course of weeks) to the surface of a painting as it dries and cures. When these compounds accumulate on the surface -- which they do, slowly and steadily -- they can interfere with adhesion of subsequent layers and varnishes.

So it is sound practice to remove them.

This can be done easily by wiping the surface with a clean, wet, lint-free rag.

Once the compounds are removed, subsequent layers (whether of mediums, varnishes, or paints) will have a better surface for adhesion.

One would expect to see some potential adhesion concerns if one were painting on a surface that had a thin film of soap on it. Most artists would remove the film before painting on such a surface. Unknown to many, a dried and cured layer of acrylic paint or medium usually has such a film.

Lady Carol
12-18-2009, 09:02 PM
I think it would be a good idea to give credit to the source in these threads that you start.

12-18-2009, 09:30 PM
I think it would be a good idea to give credit to the source in these threads that you start. There is no single source. Anyone can do further research by using Google. The word surfactants could be used to locate more information. Among many other possible searches would be "surfactants artist acrylics removing."

This thread is intended as a service to others here who might be interested in this widely neglected but quite relevant topic.

There are some additional good reasons to remove these compounds (I've avoided using terms like surfactants and detergents because some readers are put off when the discussion starts to turn or begins to sound technical): They can attract and hold particles from the atmosphere. They can also cause some discoloration.

The Tate released a study recently:

A key finding of the project has been in the examination of surfactant, a detergent-like material which stabilizes the paints when wet but which can move to the surface to produce a greyish tone when dry, attracting dirt and dust. Water-based cleaning treatments can rapidly remove this material and do not appear to have a detrimental effect on the long-term performance of these paints. The development of a successful strategy to assess and monitor the migration of surfactant to the surface of the paints and improve its removal and cleaning on artworks will have a lasting impact in the care of many modern paintings.

You can find this by using google.com, or by clicking here:


There is more at the Tate website: