There is a lot of confusion among artists about turpentine and mineral spirits. Some YouTubers promote Gamasol as an alternative to turpentine. One even recommends Gamsol as a natural substitute for mineral spirits.(?) This particular artist provides commercial seminars on oil painting!
Turpentine is distilled from the naturally-occurring resin from fir trees. It’s been used for centuries by artists and craftsmen. Is it natural? Certainly.
Mineral spirits is made from petroleum, like kerosene and gasoline. Artists have used mineral spirits and turpentine to paint with since records have been kept. In hardware stores, mineral spirits is called paint thinner. Is it natural? Petroleum is certainly naturally-occurring.
Manufacturers refine mineral spirits to eliminate its strong odor. Refined mineral spirits is called “odorless mineral spirits,” or OMS. Some artists are bothered by turpentine’s odor; other artists (like me) don’t like the odor of raw mineral spirits.
Where does Gamasol fit in? Gamasol is odorless mineral spirits, nothing more. There is nothing to differentiate it from the OMS I buy at the hardware store by the gallon–except the price.
I use both products in my paintings. Turpentine is a stronger solvent than mineral spirits. For thin passages, I use a lot of turpentine. In the early stages of a painting, following the fat over lean principle, I use turpentine exclusively. As the painting progresses, I use OMS more often.
In the unfinished painting, T51, the blue blouse shows the use of OMS. It’s more finished than the yellow outfit, which is looser and thinner and painted with turpentine.