Photoformulary's "MODIFIED WINDISCH CATECHOL FILM DEVELOPER" Seems very interesting. Catechol is often used in compensating developers and can give a very long tonal range. The developer above is also very economical. 40 liters for $10.25. They say that the part B has a shelf life of one month, but since it's only a Sodium Hydroxide (caustic soda) solution, it's very easy to mix when you need more.(posted 8050 days ago)I have the chemicals for this developer in my darkroom, but I haven't used Technical Pan for a long time, so I haven't tried this film/developer combination. I have however tried a catechol developer with lith-film with low to normal contrast as result; much better than with highly diluted Rodinal (1+200 to 1+400).