Some months ago I was trying to make a Caffenol two-bath developer like I did with Parodinal+Vit C. Starting point was equal amounts of coffee and Vit. C as bath A and then soda + potassium bromide as bath B. Before having some result I had to go on increasing coffee and vit. C concentration of the bath A until I reached 200g/liter each. But then, I realized that the amount of bath A transported into bath B was as little as 10ml/Liter. So I tought, why not adding the 10 ml of that solution directly to the soda bath. So I did and the result was as expected, this developer worked in about 30 minutes at 20ºC.
Some days ago, I remembered I still have some bottles of bath A, made some months ago. The developer was still good, which means it can be stored for several months (I added some grams of sodium sulfite as preservative too).
One of the pictures shot last weekend and developed in Caffenol Strong, the name I gave to this weak/strong developer.
Amazing is that the negative has a blueish color that, inverted, resembles coffee stain in the positive image (maybe a question of film too). The other advantage is a pH about 10,8 with very long developing time and, as far as I can observe, very fine grain compared with other relatives.
Bath A - dissolve 5 g/L of sodium or potassium sulfite or metabisulfite; add 200g coffee and 200g Vit. C and stir. Let stand until the foam vanish.
Bath B - 50g/L sodium carbonate + 1g/L potassium bromide
Work solution: 10ml of bath A in 1 L bath B or equivalent.
Developing time is about 30 minutes at 20ºC with Fomapan 100 ISO.
If one uses only 500 ml of this developer it will contain 1g coffee and 1 g Vit C.
This is almost a miracle, isn't it? Like the 1L car of Volkswagen.