Quote Originally Posted by Thomas Bertilsson View Post
If you need 250ml of stock solution to fully develop a film, at 1+3 dilution, you have to add 750ml (since that is 3x the developer stock solution, implied by the 1+3 dilution).
That makes for 1l solution.
But you don't need 250ml of stock solution (neat dev) to develop one film at a ratio of 1:3 with water. For one 35mm film you need a total final volume of 295ml (Paterson tank) and for one 120 film you need a total final volume of 500ml (Paterson tank).