The active developer is Vitamin C and the superadditive is Phenidone, long known as a low toxin developer. The developers are carried in an alkaline solution that is commonly used for a hand cream emulsifier and a pH balancer in shampoo. Shelf life is very long. It is a high concentration developer that is diluted 1:49 and can be mixed as needed. Use development times for Kodak D-76 1:2. This comes in a 250ml bottle which will make 12.5 litres of working solution with a total capacity of 50 rolls of film and a 500ml bottle which will make 25 litres of working solution with a total capacity of 100 rolls of film.