The life of the stock solution is 1 year in tightly capped bottles. This formula uses A B stock solutions. You can expect to get 10-15 rolls of film per liter of developer at a 1:1:5 dilution. The working solution has a life of 2 weeks. BW-44 is a high capacity developer and very suitable for large or small format. This formula should give the very best in shadow detail and sharp highlights. Dilution can be varied from 1:1:1 up to 1:1:20.