Quote Originally Posted by jimbop View Post
I've literally started reversal processing B&W this week, and my first results were not perfect (lack of contrast on FP4+) but certainly there was something usable (accidentally overexposed the film by 1/2 stop - maybe that's it?)!

I've done a lot of reading and seem to come across a couple of conflicting ideas regarding potential brown staining caused by a KMnO4 + H2SO4 bleach. Some methods suggest that this stain can be cleared using a Na2S2O5 solution (not sure if this is what's in the Foma clearing bath you use) but some methods suggest that Na-metabisulphite will NOT work, and instead one must use potassium metabisulphite.

Now, as I mentioned, I've started playing with B&W reversal this week and I used a KMnO4 + H2SO4 bleach with a NaS2O5 clearing bath and it worked fine... perhaps the staining issue is therefore dependent on the age of solutions?

I don't know if there's anything useful in my musings, but maybe it is worth checking/changing your clearing bath and see if that eliminates the problem? BTW - my method (at this early stage) is an almost direct implementation of that in Jens Osbahr's pdf (freely available online - and linked to on here), in which Rodinal is used as the 1st & 2nd Dev. - seemingly without any significant brown-tone issues. The only change I made was that I used Ilford multigrade as the 1st and 2nd dev. and like I said, slight lack of contrast (and possibly low D-max) - but worked with no staining.
JIm, thanks for the ideas. And for the first time, I realised that the Foma clearing bath does have the contents printed on it. It's Sodium Pyrosulphide which I've never heard being used anywhere so far.

I always planned to switch to NaS2O5 once the Foma kit was done. So I'm going to do it now as I'll have to get used to using it anyway.

It was re-reading Osbahr that made me decide to go back to Rodinal and give that another shot.

It seems that the low contrast is the bugbear of all home reversal processes. Are you using the chemical fogging agent?