Q. I recently obtained some brochures at an art exhibit extolling the virtues of walnut oil. Ive asked several oil painters if theyve ever used or even heard of walnut oil and not one answer was affirmative. What can you tell us about the use of walnut oil in place of the usual solvents such as turpentine and mineral spirits?
A. Walnut oil has indeed been in use by oil painters for centuries, but as a binder, not a solvent. Reference texts characterize it as short compared to linseed oil: that is, it doesnt flow like linseed oil and is more apt to produce crisp, stroke-showing daubs of paint. Its also a good drier, so its a good oil to use for paint making. On the other hand, nut oils grow rancid in storage if theres air in the container (this isnt a concern if the paint is in a tube)—so walnut oil-containing media might have a bit of preservative in them.
Theres one maker of walnut oil paints: M. Graham, in Oregon. Ive never heard much in the way of negative reports concerning the use of walnut oil in paint. It seems to be compatible with the other types of oil used in oil paints, as well as with additions like alkyd resin.
As for using walnut oil in the place of solvents to clean your brushes, that would be an expensive proposition and unnecessary. Instead, use any ordinary vegetable cooking oil to clean your brushes. Then, wash them in mild hand soap (any soap without conditioners or perfumes) and rinse thoroughly.
Henry Fukuhara lives in Santa Monica, California. His work frequently appears in Watercolor Magic.