Sometimes hydrochloric acid can be substituted for sulfuric acid, often not. HCl is usually called for when chloride ion is needed as well as acid. Chloride is pretty active in many photographic situations. Sulfate, on the other hand, is pretty neutral photographically. Another problem is that HCL reacts with a lot of things to release chlorine, which is nasty to both people and photographs. It's better to stick with the acid called for in the recipe unless you really know what you're doing. Incidentally, sodium chloride plus sulfuric acid is often used as a substitute for hydrochloric acid in photography.