Going to start with 1gr a liter of rodinal 1+50... but this may not be the correct proportion to the best effect.
i do not know any developer combining paraminophenol and catechol but agfa atomal combined catechol with N-hydroxyethyl-o-aminophenol and hidroquinone in high sulfite solution.
i am just wandering and maybe this combination wasnt used before because it sucks, but let´s see
Interesting experiment, as Catechol is a little on the expensive side as Rodinal is a one and done developer, wonder how it will cost out? Also what film speed?
Pyrocat-P contains catechol and p-aminophenol but some calculation or experimentation would be needed to see if simply adding catechol to proprietary Rodinal would make a staining/non staining developer. https://www.photrio.com/forum/threads/pyrocat-p-pyrocat-m.16994/
Interesting experiment, as Catechol is a little on the expensive side as Rodinal is a one and done developer, wonder how it will cost out? Also what film speed?
Have you tried developing partly in Rodinal and completing in a Catechol developer like Obsidian Aqua (or vice versa)? Does that give you additional control on grain and stain, say, by varying the time spent in either of the developers? Or is it an outright bad idea?
I read about those 2 developer a few years ago... I tryed something like hc110+perceptol but i found the results nothing special... But maybe it could be another way..., Specially with staining devs.
Another way can be bleach and redevelop with staining developer, this was already tryed, i think.
It'll more than likely have been tried & likely found to offer no improvements over MQ or PQ under meaningful test conditions. Don't associate absence with lack of research, but consider that it was probably tried & was a failure.