Hi! In color film dyes are produced by the dye couplers in the emulsion and an oxidised form(that's being produced after developing silver) of p-phenylenediamine derivatives, such as N,N-diethyl-p-phenylenediamine, but p-phenylenediamine itself works too, as well as 4-Aminophenol. If I understand everything correctly a substance with a redox potential allowing it to be a BW developer, a benzene ring and an amino group should work at least as a bad color developer. My question is, will tryptamine or mescaline(hope this doesn't break the rules, since I don't discuss it's synthesis) produce at least some colours? I don't know what dye couplers are used in modern film stocks, but there is info about ~60s couplers, I can post it if needed.