Ron - We all should know by now that in the days gone by, the sulfur content of gelatins used for photographic purposes varied greatly, depending on how much mustard the cows liked with their grass. This was figured out in the mid-1920s. I assume gelatins were still using sulfur-containing gelatins up into the 1940s or 50s, depending on the manufactuer. Todays gelatins have been stripped of these sulfur compounds to give us a more consistent performing gelatin. Since the sulfur is missing in these modern gelatins, we need to add it back in to increase emulsion speed - this is done in the final steps of emulsion making. If one wanted (and I'm not saying that would really would, but) to better emulate the emulsions of yore, I suspect we could simply some sulfur to the gelatin at the start of the emulsion making process. I assume thiosulfate would be suitable or would we want to use an organic sulfur compound which may react slower and survive the initial steps of emulsification? I can see not wanting to have the sulfur react immediately with the silver and get locked up inside the crystal, and not be available to increase speed as it would if it was on the surface of the halide crystal. At what concentrations would we shoot for? And perhaps more importantly, I realize that there will be more variation in the result with the sulfur added at the begining of the process instead of at the end, as is done with modern film emulsions. But, given that caveat, what other issues should one consider if one was to try this? Comments, thought?