In 1995, Dr. Scott Williams, along with his RIT class, developed (pun intended) a method of developing traditional black and white film with common household items. Eventually this came to be known as Caffenol.
Over the past month or two I have been experimenting with the process, which has three ingredients; Instant coffee, Vitamin C powder and Washing Soda (I’ll share my formula momentarily). The original formula doesn’t have Vitamin C powder, and is simply two ingredients. Often, having the Vit. C, lends the name Caffenol-C. There are other ingredients which some have experimented with, but for now I’ll work with just these three.
As with anything utilizing chemicals, even household, there are a few disclaimers. I have seen several people state they use this because it is “environmentally safe”. While it may be composed of basic household items, this is far from the truth. Remember, when we develop film, one of the first processes is to wash away any silver halide from the film emulsion which has basically been unused, or not exposed. This ends up in our developer, which most will wash down the drain. Just food for thought…
The good part: Formula
7 grams (about 5 tsp) Instant Coffee (NOT DECAF)
3 grams (about 1 tsp) Vitamin C powder. I’m still working with the amount of Vitamin C, and it seems there is little to no difference between using 2 or 3 grams.
19 grams (about 3 1/2 tsp) Washing Soda (not baking soda)
The bad: Development times
I have found my development times at 20 degrees C to be at, or near 10 minutes for nearly every film type. But there’s a catch. Coffee isn’t just coffee everywhere. First, decaffeinated coffee will NOT work. The reason is caffeic acid, which is not likely to be present in decaf coffee. The amount of caffeic acid will also vary from one brand to another. The generic brand I happen to be using from the drug store, gives me consistent results at 10 minutes. A friend of mine uses a different coffee, and his development times are between 20-25 minutes. I would highly recommend experimenting with film which is not important to you, until you can reach consistent results you like.
Before Caffenol-C, my most utilized developer was Kodak D76, at stock strength, because that’s all I can buy locally any more. My favorite developer was Agfa Rodinal, but that became hard to find. I have found the grain from Caffenol-C to be very similar to D76, and somewhat more pronounced than Rodinal.
Here is my process:
Pre-soak: 1 minute
Develop: 10 minutes (most films)
Rinse: 2 minutes (I no longer use a stop bath)
Fix: 6 minutes
Soak: 2 minutes in Photo-flo
Rinse: 5 minutes minimum
I had (have) a lot of expired film with which to experiment with before using a new roll. Even then the development times didn’t vary, I just had to deal with some fogging, increased grain and lost contrast.
I would love to hear what others have come up with, and learned from using Caffenol. Please feel free to comment.