jdef wrote: 'Hi Helen, I was just reading about the unique depth development properties of Amidol/bisulfite developers, and had the same thought. Have you tried it yet?'
Out of curiosity I made a half-hearted attempt with a 10:1 bisulphite:sulphite mix and, er, the results were what you'd expect for developing at low pH - you could paint the pictures faster than the film developed. I'm still interested in exploring this, albeit more out of curiosity than an expectation of finding anything worth repeating, and may try starting from the other end - ie more sulphite than bisulphite. No spare time to do it though.
To quote Jacobson's wise words: 'So far no practical use appears to have been made of this depth-development effect.'
As you can see from jandc's post this film has long development times anyway. On that note, I develop at 24 °C to cut the times down a bit, especially important as I use Xtol 1+3.