Q: An oil painting I finished a couple of years ago has
developed a section that has cracked and fallen off. I never use any
medium except turpentine, and always paint "fat over lean.” Since I
paint for a living, I'm more than a little concerned about this. The
surface was a preprimed (acrylic) canvas.
Turpentine is a drying agent. A rule of thumb when painting with
turpentine or mineral spirits is to use two parts turpentine or mineral
spirits to one part safflower or linseed oil, as the oil retains the
elasticity of your oil paint. For glazing, it is recommended to use one
part mineral spirits to two parts oil. Straight turpentine may leave
your artwork with a flat or dull finish. Painting on an acrylic-primed
surface is fine, but you cannot paint with acrylic on an oil-primed
surface because the paint will eventually peel off.
--by Camille LaPointe-Lyons