Because Caffenol is a one shot developer, I use minimal amounts of stuff in order to make it cheap enough. I have been changing the coffee brand and the original recipe that uses only coffee and soda may produce more or less fog, depending on film and coffee brand. So, I started using Sodium Chloride (table salt) as anti-foggant. First only 2g/liter and then 4g/liter. Because salt is a restrainer, the developing time had to be increased from 70 to 90 minutes at 20ºC.
The formula, for a 500ml batch is now as follows:
150 ml water
10g Soluble, not decaf. robusta coffee
3 g Sodium Carbonate (or 300ml of a 1% solution)
2 g Sodium Chloride (or 20ml of a 10% solution)
Water to make 500 ml
Develop for 90 minutes at 20ºC
Here some photos I made recently using Agfaphoto APX 100 (may be like Ilford FP4), exposed in a Cosina plastic body with a Vivitar 50mm/1.7 lens. The iris of this lens are broken, it is always full openned and I used speeds from 1/500 to 1/2000s according to light conditions.