Hello all. So I've been reading up on as much information as I can within reason about the use of nitric acid in the cooking of varnish to produce color. Of course, reading about it has made me aware of the potential problems in using varnish produced with nitric acid. Some people claim to have success and others have many complaints from color shifts to drying problems to cracking and all sorts of fun stuff. Putting all of this aside, I have three main questions, both highly related. Does anyone know what quality of nitric acid produces the production of the colorant? Is it the oxidizing quality or the strength of the acid itself? Could the unnatural oxidation be what interferes with the drying time? Also, has anyone tried to achieve similar results with the use of chemical products other than nitric acid?