Q: What are a mortar and pestle used for in painting? Someone told me I could use them to grind oil colors. Is this true?
A: Normally, a mortar and pestle aren't used for grinding wet
oil colors; using a glass muller on a grinding slab is much more
efficient. However, if you work requires small amounts of paint, a
mortar and pestle can be used successfully to disperse pigment into
linseed oil, making perfectly good oil paint.