View Full Version : Developing Harman Direct Positive Using Diafine

9-Feb-2016, 13:23
I had the thought that perhaps developing with Diafine might be a useful way of controlling the high contrast of Harman DPP. That's had mixed results.

Anyway, in the process of testing, I've realized that Diafine has the opposite effect on the positive paper that it does on normal film. Rather than generally needing a higher EI of 1.5 to 2 stops, instead, with the Harmon DPP, Diafine goes in the other direction, reducing the exposure index required for a good exposure. I'm finding that I need to rate the paper at ISO .8 instead of ISO3.

These scans are crap (I didn't bother taking very good care of them since they were test shots anyway), but you can see the point.
At ISO 3:

At ISO 1.5:

At ISO .8:

I think when I go back and redo this shot for real, I'll probably want to aim for something between 1.5 and .8, but it's a hard balance. Perhaps pre-flashing together with Diafine might control contrast more. It's difficult to say, but then I'd probably loose another stop of sensitivity in the process.

Anyway, thought someone might be curious...