Diafine is one of the developers that traditionally has been used by 'seasoning'. As the complex byproducts of development accumulate in the A bath, a remarkable and otherwise unattainable image quality is the result. The grain becomes finer, the look becomes more 'classic'.
When the developer is freshly mixed, soak a few rolls of exposed film in the first bath, then the second, to 'take the edge off'. As the developer is used, just keep topping up the solutions to maintain a constant amount of solution.
The developer will improve with use, and last forever. Certainly some films work better than others: Tri X, Plus X, TXP... experiment. TMX is very interesting in Diafine although it's not for everybody. Depending on how you shoot and how you like your negatives, you will agree or disagree with the overblown marketing hype of the 'speed boost' Diafine promises ... but it's an easy way make great negatives consistently that suit a lot of shooters most of the time.
Like so many things in photography, fashionable and conventional thought says this can't be true. But somehow we got along fine in the darkroom before computers and densitometers and stuff, and made great pictures every day for rabid newspaper editors, using Leicas and Nikons without meters. If you're interested in prehistoric photo-technology, try Diafine.
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