navygunner - thanks for your kind comments! I asked "Art Instructor" my artist about the wood grain technique. He said he painted by hand with oil color for artist, several colors and several shades. He sent me an image showing 5 oil color tubes, I can read Burnt Umber, Raw Umber, Naples Yellow and 2 more which I can't read. Hope this help!
Karl - thanks for your kind compliments!