I processed some roll film this weekend to get an idea how Caffenol CH and Caffenol CL work and to get some baseline development times… First try was with Caffenol CL using Reinhold’s recipe at caffenol.blogspot.com and with Fuji 100 Acros 135. The exact recipe I used is as follows:
500 ml. water
8 g. Sodium Carbonate (anhydrous)
5 g. Vitamin C powder (from The Vitamin Shoppe)
0.5 g. Potassium bromide
20 g. Cub Foods’ generic instant coffee
I used a 500ml steel tank and reels and processed the film for 70 minutes at 68 °F (20 °C), only agitating for the first 30 seconds and then letting it stand for the next 69 minutes. I then rinsed with water for 1 minute, fixed with Ilford Rapid Fixer (1:4 dilution) for 2 ½ minutes, and rinsed again for 30 minutes. A drop of dish soap was mixed with water at the end of rinsing as my wetting agent.
The negative density looked good. Maybe a tad too dense for traditional printing but certainly more than acceptable. The problem is there’s non-uniform fogging/staining. My first thought was that maybe it could use less development but then I also read through Reinhold’s blog about agitating more if there’s uneven fogging. The staining may have been the result of incomplete/improper mixing–the coffee crystals may not have been completely dissolved before I used it. I will let it set for a few more minutes next time. I also thought about adding more restrainer (Potassium bromide).
Next I tried the Caffenol CH for my Ilford Delta 100 120 film. Here’s the recipe I used:
500 ml. water
27 g. Sodium carbonate (anhydrous)
8 g. Vitamin C powder
0.5 g. Potassium bromide
20 g. Folger’s instant coffee
The film was processed for 15 minutes at 68 °F with 10 agitations for first 30 seconds, 3 agitations every minute thereafter. I washed, fixed, and washed again as before.
The resulting negative looked really good as far as density is concerned. The problem is there’s also a little bit of uneven fog running along the middle of the roll although not as bad as with the initial Caffenol CL test.
I also tried the same recipe/development strategy with a 120 Ilford HP5+ film to get a baseline. Well, the result was pretty much the same… but the uneven fogging was worse. Next time, I’ll add more Potassium bromide to the recipe.
Then I tried the Caffenol CL again with Ilford HP5+ 120. This time I doubled the Potassium bromide and shortened the processing time to 30 minutes. Also, instead of letting it stand without agitation for the entire time, I agitated at 2, 5, and 15 minutes. The resulting negative was a little too thin (probably barely usable for traditional printing but can be digitized/scanned) but now the uneven fog is pretty much gone! Next time I’ll increase the development time for this film to maybe 40-45 minutes.
My last experiment was to process 2 different rolls of 135 film–a Fuji Neopan Acros 100 and an Ilford Delta 400. I used the Caffenol CL recipe with 2 g/l Potassium bromide ratio and developed at 40 minutes with agitation in first 30 seconds, and then at 2, 5, and 15 minutes. The result was mixed but it gave me a good idea as to how to proceed with those 2 films in the future.
The Acros 100 was a little too thin, meaning it needs more development time (and maybe less Potassium bromide). There is no uneven fogging, however. The Delta 400 was too dense and seriously fogged. This means I have to cut back the development time and maybe even add more Potassium bromide.
What I learned… Well, I now have a pretty good idea how to process the Fuji Acros 100 135 and the Ilford HP5+ 120 films. This is good since I like the Fuji Acros a lot. I’ll also need to nail down the formula and timing for the Ilford Delta films as I use those a lot as well. There will be more playing around in the next few weekends then on to serious photography and processing.