A professional photographer that I work for years ago used diafine. Its great for batch processing when you have different types of B&W films, you can process tri-x with plus-x for example. The times will be the same for any film and any temperture. The only drawbacks is an increase in film speed by about 2x. Tri-x will have to be shot at 800 asa, plus-x at 250. I may be wrong about these figures as its been awhile since I used it, but its close. If you are in a hurry and have a large batch of diffent speed films its great. But....forget the zone system as there is no way to adjust development. You are also pushing the film quite a bit.(posted 9599 days ago)