June 17, 2010
I decided to delete the recipe, since Caffenol-C-L is much better.
PS: I also deleted the recipe because my notes about it were not correct, as I said here before. Restoring impossible. That was never a reliable recipe. So save any angry comments. Sorry for any unconveniance. I don't follow this path any further. But general thought here still might be of interest..
Some people suggest reducing the pH to reduce fog and grain. Borax is suggested as a mild alkaline. My first trials with borax were not encouraging, but why not reduce the soda? So I made a somehow "lighter" Caffenol-C-M, hoping to tame the developer with highspeed films. No scientific approach at all. I took a Fomapan 400 as 120 film, loaded my 65 years old Bessa 66 and shot the roll without metering the exposure. To be honest, I forgot my meter at home. All 12 images were nicely usable, though about 1/2 was overexposed. I estimated for 400 ASA, maybe the Fomapan 400 should be rated higher. OK, only one film, and my first Fomapan400 in Caffenol.
This pimped Caffenol-C-M contains 1/2 of the Vit-C and much less soda, but the same amount of instant coffee as before. pH is 9.2 instead of 9.7 before. If we go below a certain pH, development will probably stop completely. This point I still have to examin. For low pH-Caffenol it is more important to measure the soda exactly and use the right one, be it anhydrous or hydrate with recalculated amounts - see "soda-myth-and thruth"-post. Because the lower the pH, the smaller the different amounts of soda to make big changes. I hope you got a weightscale in the meanwhile ;-)
Results: low fog level, grainy but "nice" grain, sharp, wide tonal range, probably more than boxspeed.
Click on the images to enlarge as usual. Crop is 10x10 mm neg size. 3 more images on Flickr.
Have fun with coffee - Reinhold