In the soup 3: eco hand-processing
No matter what the origins of the “caffenol” process, it provides a really great option for filmmakers working in black and white to experiment with a nontoxic process. The developer can go down the drain as no silver has leached into it, but the fixer (more about this after the caffenol recipe) must still be disposed of properly as it contains silver, which is harmful to man and beast when it gets in the water supply. And like all photo processes, in order to make sure your negative remains in good condition, it is necessary to really rinse the film with several changes of water for at least 20 minutes. This wastes water, a resource that we increasingly need to think of as finite. So these are problems that environmentally minded artists need to think through. (Digital processes are just as environmentally hazardous, although we outsource much of that hazard to China and other countries for manufacture and disposal, and thus are somehow blind to the extraordinary environmental cost of obsolete digital technology.)
Hand-processing with caffenol requires much the same tools as any other hand-processing technique. If you haven’t read it already, please review the handprocessing section of Chapter 5 to determine your developing strategy (e.g. using a Lomo tank, jamming the film in a can, etc.). The chemistry works well at slightly above room temperature but isn’t terribly temperature sensitive, so a warm bath with tap water should be fine. The process does take a bit longer than other black and white chemistry, so using a Morse tank (reel to reel) does not make sense. Some people use volumetric measurement (e.g. teaspoons, tablespoons, etc.) to dish out the chemistry and others insist on weight. Strongly recommended are pH strips that can measure the full range (1-13) as is a straining device, especially when using grass, leaves and other plant material. However, you’ll find folks who embrace the chunks of organic material deposited during the process as desirable. Like most hand-processing techniques, if you want a lab look, this isn’t for you. What follows is a recommended list of materials in addition to those recommended in Chapter 5 for hand-processing.