510 Pyro Concentration >1%

Ian Leake

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I've been using 510 Pyro for a while, always in the recommended 1% (1:100) concentration. I use semi-stand development for roll film, and open trays for sheet film. For sheet film, I develop for 20 minutes or more, for significant expansion and density, shuffling the stack of film every minute.

Does anyone have experience of using 510 Pyro at a higher concentration, e.g. 2% or 3%? I'm thinking about testing this with sheet film in open trays. Presumably this would reduce development times, but will it also introduce new problems?

Thanks in advance for your thoughts.
 

koraks

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Yeah, I've done that, for redevelopment after chromium intensification. It works and it's faster than lower concentrations. I never really looked into it very deeply because 510 has the nasty habit of throwing down an overall stain that may look pretty, but in reality is just global density without much benefit. Mind you, it also makes image-wise stain that probably does something to your image, but I found the global stain objectionable because it greatly affects printing times for alt. processes.
 
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Ian Leake

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Thanks. I don't mind global stain density so much, so long as there is also additional density where it's needed. I'm still 'emotionally attached' to John Wimberley's WD2H+ for pt/pd, so I'm still experimenting here. I guess it's time to do some testing.
 

koraks

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The overall stain is not a problem when enlarging or scanning the negatives, so for most it'll be a non-issue.
I didn't really take note of the difference in activity between 1%, 2% etc. dilutions, so I wouldn't be able to say if you can expect a linear relationship between dilution and development time. I wouldn't expect so since pH will remain fairly stable and density is logarithmic, so I expect a law of diminishing returns as concentration goes up. But that's kind of a haphazard guess, I admit.
 
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Ian Leake

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I think I'll do some BTZS testing with 1%, 2%, and 4%, and see what happens. It's not my favourite thing to do with my darkroom time, but sometimes unavoidable.
 
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