I know that 68F (20 C) is the magic temp and since I mix my Rodinol on a one shot bases, it is easy to develop film at that temp. My Stop and Fixer chemicals are stored in a corner of the basement and rarely get above 73 F. which does not seem to be an issue. The problem is my paper developer, I am using Arista Premium paper developer and I need about 32 oz. (1 liter) to fill my development tray for 5x7 prints. This is enough for about 60 5x7 prints and I rarely print a dozen, so I save the developer between runs. Usually I place the developer container in cool water until it reached 68 F. I have heard conflicting comments on the necessity for keeping a tight temp control for paper development, so I wonder how other feel about it.