The caffenol recipe I suggested to Digitaltruth Photo is very sensitive to Sodium Carbonate amount and coffee quality. I started then by adding some table salt to prevent fog and it works. The addition of salt must be compensated with an increase in development time because salt retards the development. For 2g/Liter of salt an increase of 10 minutes is enough and for 4g/Liter a further increase of 10 minutes should work. So, instead of 60 minutes, 70 or 80 minutes (or more) for 2 and 4 g/Liter respectively should be considered.
My last roll was developed with 4g/Liter salt but the development last only 75 minutes and it is a little underdeveloped, dark shadows without details. Next time I will develop for full 90 minutes with 4g/Liter salt. Just to see if it is too much, or not.
Here some pictures of the last roll, I took last weekend in Tavira: