"Black Oxide"

About 5 years ago, I used to sell chemicals in Berkeley, California. We used to sell a lot of products to artists for patination of sculptures, that sort of thing. We used to get a lot of calls for a cold black for steel similar to a product called "Birchwood Casey." The company that makes this has a fairly large minimum order, or used to, so I formulated a comparable product which I sold in a 16 ounce size. I didn't "reverse engineer" their formula. I started with a public domain formula, and tweaked it until I got a coating that wasn't powdery, and didn't rub off. I called it "JetKote 54."

Is there much call for this sort of thing in industrial metal finishing? I understand that it's nothing like real black oxide, but I think it might have its place for some people. I'd like to start brewing it up again, if it does.

Any feedback would be deeply appreciated.