RAF Pyro-Metol

[David A. Goldfarb]

part A

metol 3.9 g
potassium metabisulfite 4.4 g (or substitute 5.1 g sodium metabisulfite)
pyrogallol 4.4 g
potassium bromide 1.6 g
water to make 1 liter

part B

sodium carbonate (crystal) 108 g
water to make 1 liter

Mix one part A plus one part B immediately before processing and discard after use.

Staining developer that produces a true speed increase. Grain is significant, so better for medium and large format than 35mm.

I'll post more development times and speeds as I test this with more films. I suspect that this will work best with films that stain well like Tri-X, Efke 100, FP-4+, and Classic 400.

See this thread for discussion, sample photos, references, and a good suggestion that there is a small error in the formula as it appears in Haist (the above formula is converted from Haist; Haist is converted from Erith, most likely substituting US ounces for the original British ounces)--

http://www.apug.org/forums/forum37/17245-raf-pyro-metol.html

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Old Tri-X 400 (TX), EI 3200 for daylight, EI 1600 for tungsten, 4.5 min., 75 deg. F, agitate first 10 sec. then two inversions every 30 sec. Sample photo (6x9) with detail-- http://www.apug.org/forums/attachme...tachmentid=2372

[Sean]

Comments from previous article system:

By David A. Goldfarb - 02:43 PM, 07-24-2005 Edit Rating: None
TXT (Old Tri-X sheet film), EI 1000, 4 min., 75 deg. F, in trays cycle through the stack once every 30 sec. It's really easy, though, to go overboard with the contrast with this combo. In hard light, it's worth considering cutting development by 20-40% or trying a more dilute solution, and in really low light increasing the development time. I haven't worked out - and + times for this combo, and I probably don't have enough of the old TXT left to justify that kind of testing until I've switched over to the new version.

If you want to err on the side of caution or just nudge the shadows a bit up the curve, rate it at 800.
By David A. Goldfarb - 01:02 AM, 08-01-2005 Edit Rating: None
I ran another test to see if it is possible to do two batches in rapid succession in the same developer, as one can do with ABC pyro, and it worked fine. I put two sheets of TXT 8x10 through about 32 oz. of developer, then did another two sheets at the end of the run after moving the first two through the fixer and then to a holding bath, and they look just like the first sheets. Given how short the development times with RAF are compared to ABC, it might even be possible to get a third batch in there.