Pre-wash of film - good or bad???

[Roger Cole]

Uneveness in Jobo drums is often due to another cause, since their drums fill and drain slowly. I can fill or drain one of my 30X40 inch print capacity drums faster than a single-roll 120 film capacity Jobo drum.

If that was in reply to my comments, I do have a Lift, so it at least doesn't SEEM that slow.

In any case I'm concentrating on medium format for a bit until I can replace my elderly basically falling apart old Technika III. When I get a new (or new to me) 4x5 camera I may upgrade to a larger Jobo and the Expert drums at the same time. I've had no issues at all with my CPE2 and 120 or 35mm.

[Drew Wiley]

The slowness of filling and draining Jobo drums is due to the tiny opening in their funnel-like lids. I don't use any kind of lift, even on 30X40 inch drums. That makes no difference. I routinely use a Jobo hand-inversion drum for developing 120 black and white film, but have doubts about the consistency of the bigger print ones if short developing times are used.

[Vaughn]

Fortunately speed of filling has not been an issue yet for me (drums 3005 and 3006 on Unicolor motor base, 4x5 to 8x10). I give the film a good pre-soak, then it might take me up to 20 seconds to pour a liter of developer into the rotating drum. There is a limit to how fast one can pour into the drum without the liquid backing up.

On the 3005 drum, if I read it right, there is a 270ml minimum liquid recommended. So even if it takes me 20 seconds to pour in a liter into the rotating drum, I hit the minimum developer needed in 5 to 8 seconds -- after that, the speed-of-filling is no longer critical because all the film already has sufficient contact with developer that will not exhaust nor significantly weaken by the time I slowly pour in the other 730 ml.

Does that sound reasonable, Drew?

[Drew Wiley]

It's all relative, Vaughn. But it takes me only about 5 sec to fill or drain even one of my big 30X40 print drums during rotation because that is not reliant on a center hole, but entry through the entire light-tight rim diameter. Another thing that helps is to limit the percent of time of filling or draining relative to the overall time of development, for example, in RA4 processing, standardizing on 2 minutes instead one 1 minute. As per film itself, yeah, I'm convinced that a short pre-soak is essential to fast even spread and entry of the developer itself.