porridgeoats

Thanks for the recommendations. The Massive Dev Chart is a very valuable resource for sure- one I've used a few times. However, what I'm really looking for is the method by which the manufacturers arrive at these recommended times and temperatures. It's of interest to me as I'm currently trying combinations of homemade developers as a side project and I'd like to see if there's a way to get an optimal time, outside of simple trial and error.

Hi all, I'm new to the forum, but I've been reading posts for some time. I've been recently getting into the chemistry behind film photography but I'm struggling to find useful articles for how film manufacturers actually calculate a development time for a given film in a given developer. Obviously, you could establish a rough estimate through trial and error. I've seen a way of estimating by: Dipping a portion of film in the developer (specifically dip, not keep submerged) Count the time (in seconds) that it takes for the dipped side to turn the same colour as the undipped portion Given these time, divide it by 3 and that is the time (in minutes) that this film should be developed in the given developer at the given temperature This is obviously reminiscent of the fixer trick. It also only gives an estimate (and I've only seen it mentioned a handful of times, surely if it was that effective it'd have more renown?). Then of course there is the zone system and "by inspection". Any help you guys can give would be greatly appreciated.