Bruce-yes I get box speed from this combo. It's 120 so yoour going to have to try the 35mm. Hey I just bought some of the High Resolution film at the conference...move over Acros....
Yep. Works just fine. Actually, that's probably more Phenidone than I need. I got the basic ratios of that formula from some old Photo Techniques article that Pat Gainer wrote, but I believe (though I may be mistaken) that he subsequently determined that the optimum ratio of Phenidone to ascorbic acid was 1:40. But I've never bothered to change since I love the results I get now.
Originally Posted by dancqu
Phenidone is certainly some Fantastic developing agent.
Originally Posted by Maine-iac
Almost none is required. One formula I encountered for a
one liter concentrate uses 1 gram of phenidone. That liter
is to make 50 liters working strength; .02 grams per liter.
No mention though of a liter's working strength capacity.
IIRC, Mr. Gainer's interest was with the regenerative
aspect of the ascorbic acid-phenidone pair. Ratios
above 1:40 did little to further increase activity.
That is not though the only basis for deciding
upon a specific ratio. Dan
One liter of my formula might even develop more than four rolls of film; I've just never tried it. Since I have a two-reel (120) tank, if I've got four rolls to run at one time, I develop the first two rolls at my usual time (6:30 for Delta 400), then load the other two rolls and run them through, increasing the time about a minute. I can't tell any visual difference between the two runs. I'm fairly certain that if I did a third run and increased the time a bit more, the capacity would be there to develop them just fine too. The Phenidone/Ascorbic acid combo is potent. And it's so simple, cheap and convenient as well--three ingredients counting the alkali, and by switching between metaborate and carbonate for different films, it's also very versatile.
Processed two rolls of 120 Acros 100 this weekend in Ilford LC29. The data I found for this combination was 4-1/2 minutes at 1:19. As this was for ISO80 and I had exposed for ISO100, I developed for 5 minutes - negatives looked great (as do prints!).
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