MITRA Forum Question Details

​We feel that it is "ok" to use the paint inside IF it is still wet AND if you do not incorporate any of the "skin".....the latter is harder to do. Realize that even though the paint beneath the skin, even if it is still wet, has probably begun to oxidize to some degree but you can still work with it to a degree.

To be clear, it is always important to use fresh paint. Ralph Mayer has a very good section on this in his The Artists’ Handbook. The degree of importance varies from medium to medium. Obviously, for traditional watercolor and gouache, the issue is of little importance as the paint is completely resoluble. It is paramount in egg tempera.. It is in the middle for oil paint. The issue is that you want the paint to go through its whole drying or setting curve in place and not interrupt that, which can diminish adhesion. This is different from adding partially pre-polymerized/oxidized mediums like thickened linseed oil as these are in addition to the amount of binder need to adequately produce a serviceable paint.

While there are certainly examples of modern and post-modern artists incorporating paint skins into their works, I would caution against it unless that is the specific effect that you are searching for and not just a result of your attempts at economy.