I have followed these discussions for a very long time and as best I can tell there is not one single solution that works in every case. People are using drums with different internal configuration (smooth walled, ribs, tube separators, etc.), different developers and dilutions, and developing for different processes (what works for silver printing may not work for alternative printing). What I can suggest are a few guidelines that I try to follow.

1. If possible use a drum with a smooth wall configuration. The tubes, ribs and separators that are in some drums may alter the rate of flow over the developer during rotation and create hotspots. And the hotspots may not be visible in silver printing but may show up in printing with UV processes. Having said that, I have personally had good success with Beseler and Unicolor drums that have internal dividers and ribs.

2. Use the most dilute solution of the developer possible, If using Pyrocat-HD or -MC use the 1:1:100 dilution, or even 1:1:150 instead of 2:2:100. If using D76, try 1:3 instead of 1:1 or 1:2.

3. Slow rotation is much better than fast rotation. The Unicolor and Beseler motor bases rotate the drums much slower than Jobo. If you have a Jobo, use the slowest rotation possible.

4. Motor bases that reverse the rotation are preferable to those that turn in one direction only.

5. Right after you pour the developer in the tube lift it from the motor base and give some rotation on end by lifting the ends of the tubes up and down, rotating the tube at the same time. Repeat this action every minute or every two minutes for the rest of the development period.

You may not do any of these things and still get good results but IMO they are best practice for developing film in drums with motor base rotation.

Sandy King