Making Walnut Oil

The Old Masters would have ground most of their own pigments, or in the case of the more successful ones-had assistants do the work them. Along with this they would have had an intricate knowledge of the best ways to prepare each pigment. They could maximize the brilliance and longevity of each color.

Some of the mineral pigments that I'm preparing to make are better suited to different binding mediums. The linseed oil that I've used to mix most of my paints is not really compatible with these colors. So this week I started preparing some walnut oil.

The process is the same as for preparing linseed oil. The walnut oil will need to be cleansed of natural contaminants before I can use it. I will do this using water and sunlight.















Here is the walnut oil I'm going to be using. This is a decent California brand, bought from the grocery store.

I added distilled water into the oil, shook the mixture thoroughly, and left it out under the sun.















I waited about 3 days. The water and oil have separated. The mucilage and other contaminants are trapped in between the two.















Here's a close up shot. The layer of mucilage is really visible here.















Yuck. A top down shot that really shows the mucilage well. It has already discolored noticeably from only a few days in the sun. This would be a major contributor to yellowing and other discoloration in a painting if not first removed.















I very carefully removed the oil from the top using a pipette. The oil is noticeably clearer now than before. I will repeat the process several more times until I'm satisfied I've gotten it clean.