Hi all,

A quick question that hopefully has a relatively simple answer... I’ve read Sandy King’s website and a few others to find information on what I’m after but with no luck so far...

Normal dilution for Pyrocat-HD for negs aimed at silver printing on VC papers is 1:1:100, but I know a stronger 2:2:100 dilution is often used if doing 5 sheets of 8x10” film at a time in an Jobo 3005 expert drum, where the max chemistry load is 1L and exhaustion is likely with standard dilution.

My question is this: how much more active / faster working is the 2:2:100 dilution relative to standard dilution? Is there a standard formula or rule of thumb I can go by to convert a 1:1:100 dev time for a given film to 2:2:100 at the same temp, or is very much emulsion specific and too variable to predict?

For context, I’ve already got good data for times with some films thanks to Sandy’s great work and helpful information provided by people here, but have decided to bite the bullet and order another box of Pancro to test and the only data I have for it (supplied by Bergger) for Pyrocat is:

Dilution 1+1+100
Température 24°C
Speed 200 : 17 minutes (contrast 0,65)

The time seems very long-although all of their recommended times are-especially at that temp, and I don’t think standard dilution would hold up that well with 5 sheets in rotary processor for that length. 2:2:100 seems a better option to guard against exhaustion and would cut time down, my question though is by how much? Beyond Pancro, I’m interested in the answer / formula / rule of thumb guide so I may apply it to other films I might want to try where information is scarce.

Thanks!