Nothing in this thread accounts for the statement, on Rodinal packages, going back several decades, that hydroxide is only 3%.

A 1998 MSDS confirms this; in its entirety it gives

potassium hydroxide, 3%
potassium sulfite, 30-40%
potassium bromide, 1-5%
p-Aminophenol, 1-5%

and the pH is 14 (!!!) - - which is massively higher than other figures, published by Agfa, that we have all seen.

It is obvious from this disclosure that many ingredients off the list are present, because it is unlikely you could make up any combination of this formula and have a stable liquid capable of developing film in a reasonable time at 1:100 dilution. The secret is pretty obvious, even without the hints Agfa published in the literature of the 1950s and 1960s.

As I have said before, Agfa agreed to allow Bob Schwalberg to publish all manufactured formulas for Rodinal since its inception except the then-current one, which was as radically different from its predecessors as they were from theirs. This was one of Bob's last projects, in the latter mid-1990s, and was frustrated only by his sudden death. The main points were: 1. there have been many formulas, 2. no published formula has ever been accurate, 3. there are many surprises.

Well, it's only ten years later. Who's up to tracking down the surviving Agfa b/w honchos and getting them to agree to re-open this? Not me - - my conversational German isn't up to it.

My theory throughout life has been: if you want a good answer, go to the world's expert. Why is it that I remain the only person around willing to do this? But I can't do the Agfa people - - there's too much of a language barrier.

By the way, I noticed that nobody has taken up the most interesting educational remark made here, which was by Ron and the relationship between potassium bromide and edge effects.