I'm considering jumping into Van Dyke Browns or argyrotypes, but I'm a bit concerned with their archival qualities. I see they can be toned with gold, platinum, selenium etc., none of which really appeal to me because of cost or toxicity. What about sulfide toner, like Kodak Brown Toner? It seems like the finely divided silver particles these processes produce would tone very well with sulfide, yet I see no mention of it.

