Having searched far and wide for good information on solvent-free oil painting techniques I thought I would have to give up this dream. Then recently I found Tad Spurgeon’s site. Tad has done has done extensive research into the history of oil mediums and the history of solvent-free oil painting. He has come up with several great formulas used by master painters of the past. And he has been kind enough to share his information with us for free. You can read about Tad’s tests and research with walnut oil and other mediums at his site. http://www.tadspurgeon.com/techniques.php?page=techniques