8x10 negs with a Jobo CPE-2

[Doc W]

I have heard that it is possible to process two 8x10 negs in a CPE-2 with a 2830 drum. Has anyone tried this? What about the CL81? I would be interested to hear about people's experience with that too.

My old ATL-3 died and I need a quick alternative until I find a CPP/CPA in my price range.

 

[DREW WILEY]

You could roll a drum back and forth in the bed of a darkroom sink or even on a floor. Some people even roll giant dev drums on sidewalks. It works. The biggest problem with Jobo gear is the degree of dev oxidation due to excessively high RPMs, even at the lowest settings, and the long time necessary fill and drain between steps (esp w the ATL rigs!). But people do it all the time, given the right dev choices.

 

[Doc W]

Drew, in my darkroom environment, I require some degree of temperature control, especially in cold weather when I use space heaters. That is the main reason I use the Jobo. In addition, I have found that unless the drum is turning when I add developer, the development can be uneven. I have hand-rolled expert drums but I frequently get uneven development.

 

[grahamp]

I use a 2833 with 8x10 HP5+ and Thornton Two bath. It works fine. Do base your developer volume on the film area and developer capacity. The paper drums quote minimum volumes for paper developer. Two 8x10 sheets is abut the same as two 35mm films, so in my case I am looking at a minimum of 200ml. I usually use 500ml as it is a reused developer.

The drum ribs do not give me any trouble with marks, but other film stock might be more sensitive. I usually put a bit of masking tape on the drum adjacent to the common rib when I load the film to make it easier to get orientated.

 

[DREW WILEY]

Just use a water jacket. I have gear to keep dev temps within plus/minus 1/10th deg F. That's ridiculous overkill for most processes. Another clue: It's the temp INSIDE the drum that counts. I happen to mostly use superior noryl plastic drums, but even the thin ABS drums like Jobo uses can be made far more insulating with just a neoprene wrap like a wet suit. But admittedly, I gave up on drums for sheet film a long time ago.

 

[GregW]

I've used a 2840 to do 4 5 x 7's in my CPE plus with a lift. I would think 8 x 10s wouldn't be appreciably different. Make sure your clips to secure the film are fresh and hold on well. Old heavily used ones may have less of a grip and may pop off. I use about 200ml-240ml of chemicals (Rodinal 1:50)
Catlabs also sells a special holder to process 3 sheets at a time in a multitank 5. It's a CL81.