pyrogallol & pyrocatechin

From: Gordon J. Holtslander ^lt;>
Date: 04/02/04-09:15:40 PM Z
Message-id: <>

I'm wondering if I can tap the collective mind of the list.

I use a low pH phenidone ascorbic acid developer to produce continuous
tone negatives from ortho lith film. It works well, but suffers from slow
speed and poor shadow detail - its essential to pre-flash to get any
shadow detail.

I've been intending on experimenting with adding pyrocatechin to the
developer to see if it resolves some of these issues. pyrocatechin is
superadditive with phenidone, which may increase the speed. Is pyrogallol
superadditive with phenidone? I've also read (where I don't recall) that
a pyro was favoured in the past as a developer that exposed shadow detail
well. I don't remeber if it was pyrogallol or pyrocatechin.

I've gone through my chemistry collection and noticed that I have some
pyrogallol. I'm considering trying pyrogallol to see if it can do the

My question is to what extent can I assume pyrogallol and pyrocatechin
will produce the same results in this situation. I should probably assume
nothing :(



Gordon J. Holtslander Dept. of Biology 112 Science Place University of Saskatchewan
Tel (306) 966-4433 Saskatoon, Saskatchewan
Fax (306) 966-4461 Canada S7N 5E2
Received on Fri Apr 2 21:15:51 2004

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