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Pyro developers and sulfite

rwboyer

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Oct 16, 2009
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MD USA
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Been playing with Pyro developers for a long time and have uses for a few of them. I plan on playing around a little bit over the next couple of months but was wondering if anyone else has already done the testing and can give me an overview of the effects of adding or varying the sodium sulfite concentrations in various Pyro formula's.

Generally I have used and continue to use regularly:

ABC/D-1

A variation of D-7 that I picked up somewhere that I guess is closer to WD2D than it is to D-7 in that it omits the sodium sulfite (Solution B) and plays with the ratios in Solution A.

PMK

Pyrocat HD.

With the exception of ABC most of these developers omit or have a relatively weak sulfite.

Anyone know what happens in general as you add sodium sulfite to formulas like Pyrocat / PMK / or use the original D-7 formula? Prior to playing around it's hard to extrapolate given that they are all Pyro/Elon or Pyro/Phenidone vs. ABC that is a single developing agent.

Thanks

RB
 

Adding more sulfite to these formulas will eventually kill the stain. Pyrocatechin based developers like Pyrocat-HD are much more sensitive to additional sulfite than pyrogallol based one.

BTW, in Pyrocat-MC the sulfite (which is in Pyrocat-HD in the form of sodium metabisulfite) is replaced with ascorbic acid, which functions more or less the same.

Sandy King
 

Thanks - Couple questions Sandy.

1) I get perfectly acceptable stain on LF with ABC as long as I use it in trays so I assume that as long as the concentration stays there or below staining will be fine? (ABC is useless for me in tanks/reels for roll film and the speed will be low)

2) Haven't tried your MC recipe - any difference to HD in Tanks or Trays?

3) I am playing around more for aesthetic differences more than I am trying to solve any "issue". Ie - grain masking v. acutance v. curve shapes at similar CI (as if I couldn't find anything else to do)

RB
 

The main problem of ABC Pyro is that the stock sulfite solution in water goes bad with time, and this in turn will impact the kind of stain you get. If you use it in tanks with the film on reels make sure to give frequent and sufficient agitation.

HD and MC give similar result in tanks and trays. MC was primarily designed to give more acutance than HD with rotary agitation.

Sandy King
 
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