Jobo speed settings (RPM)

[Rob Landry]

Have any of you Jobo users (CPA/CPP specifically) ever checked the actual rotation speeds on your machines? I know that the manual suggests setting 'P' for all 1500/2500 series drums and setting '4' for 3000 series drums. Despite always using these settings, I've always felt that these speeds seemed a little fast, so I decided to check. My father has a fancy Snap On digital tachometer that I borrowed, however, simply making a mark on the side of one of your drums and counting the number of revolutions in a minute.

With my older machine (serial #14XXX), I found that setting P was 96 RPM and setting 4 was 82-85 RPM. Before I embark on a plethora of tests to satisfy my anal retentiveness, does anyone have any idea how the rotation speed affects the E6 process? Contrast??

 

[hka]

Jobos advice for the 1500/2500 tanks is 70 RPM that's on my CPP around number 3 on the dial. For the 3000 tanks they go for the slowest possible speed let's say about 30 RPM or "F" (Film) setting. This in case of not damaging the motor. Some one prefer for 3000-tanks also rotating in "one-direction".
The "P" setting is for Papers or when you develop C41 during the bleach or bleachfixer, also in "one-direction" and change this halfways over. If you want to measure the velocity bij counting the rotations do this while the tank is filled with the normal amount of fluid for development and also in 'one-direction" modus.

 

[davetravis]

Rob,
I use the CPP2 for my E6 and found the recommended speed to be a little fast for my Fuji films, but perfect for my Kodak films. Too fast tended to over-develope and increase the contrast, so I slowed it down one setting and am getting much better results.
Good luck.
DT