runs an art materials store in Brooklyn, NY. He is a strange old guy with very strong opinions about how paintings should be made. If you are an artist, his shop is full of needful things. If you call him or walk into his store, you won't be able to escape having a very long conversation about art, in which he tries to figure out what kind of painter you are so that he can recommend what you should buy from him. He is something to experience, although you should by no means treat all of his opinions as gospel.
He makes oil paint. It is, unlike any other brand that I am aware of, ground in a blend of linseed and walnut oil. The paint is really good stuff, highly pigmented and very fluid. No one makes better blues than Robert Doak. It is amazingly inexpensive for top of the line paint. The paints are made to maximize quality rather than shelf life, so they often separate in the tube. That's OK; just squeeze the paint out onto absorbent paper, wait a minute or so for the extra oil to settle out, and transfer to your palette with a knife. It's worth the trouble.
Robert has no web site; he only recently began accepting credit cards (before that, mail order was done by check, and if he'd done business with you before, he'd mail out your order on the strength of your promise). Robert Doak & Associates, Inc., can be reached at 89 Bridge St., Brooklyn, NY 11201, or by phone at (718) 237-1210. Call before stopping in, as he's not there every day. If you are a painter in oil, watercolor, tempera, pastel, or any other traditional medium, you owe it to yourself to get in touch with him. When he goes, there won't be any more.
Updated information on Robert Doak's paint here.