Here's what we did for the 'Coffee, Anyone?' Super8 workshop where we used Caffenol - developer made using coffee!
We shot on Tri-X Super8 reversal, but processed the film to negative by using the following mixture:
40g instant coffee (Co-op own brand)
54g washing soda crystals (bought off ebay)
16g pure vitamin C powder (from Holland and Barrett)
Put 800 ml water in a bucket. Then put 40g coffee in a container and add 200ml boiling water. Add this mixture to the water. Then add the 54g washing soda crystals and stir (or swish bucket) until dissolved. Next, add the vitamin C powder. Your developer is ready!
We used this developer for 22 mins at about 27 degrees Celsius (but it cooled down over the processing time). Then pour the coffee out of the tank, rinse well, and fix (with any fixer) according to instructions. We fixed for 5 mins. Then rinse. Then dry. Then project your negative film! Some beautiful results! The developer doesn't keep well, so we used fresh for each batch of 2 films.
Cheers to everyone who came, it was loads of fun!