JOBO speed question
So I have been using a Jobo processor for a while on and off. There are two operation speed (1, 2) and I have always used speed two. But what typically do people use speed 1 for? I would imagine it reduces contrast a little and maybe its good for higher contrast films, but are there any effects on development time, or should one try to process one speed over another?
stick to speed 2. jobo recommends it from what i've read, and i've never noticed a difference in contrast or dev time between the two.
Speed 1 I.E. the slowest was recommended for processing papers. The later versions of the JOBO processors did away with the 2 speeds so stick with the fastest.
I believe the different speeds are for the different size tanks and load you are putting on the machine.
for example small tank two 35mm rolls will require one speed
large expert tank full of 4x5 film will require a second speed.
http://www.catlabs.info/ will be able to give you the complete answer Omar is great.
The two speeds settings are as noted above for roll film and for sheets (film paper).
Jobo recommended a slower rotation speed for sheets or prints for larger machines, and had the two speeds on the CPE2. You can use the slower speed for pre heat or prep time, but you should use the higher speed when processing film.
There a long APUG thread about varying results with the different speeds when processing 4X5. In our experience in the field, the slower speed actually lends to better results when processing sheet film, but has no noticeable benefit when running roll film, other then less agitation, and therefor slightly longer dev times, but that is only relevant when processing color or e-6, and perhaps also super short BW runs.
Thank you so much everyone...
The Jobo CPP2 has speeds '0' is off, 'F' through '7' go from 25 rpm to 80 rpm. The normal speed is 'P' approximately 75 rpm for1500, 2500 and 2800 tanks. '4' is for the 3000 series tanks and is approximately 50 rpm.
I do not know why so many people got it wrong, even the folk at CatLABs. I do not think it was Omar since he should have gotten it right.
I own different versions of CPE2, CPA and CPP. The CPE2 manual clearly states that the slower speed 1 is for film and higher speed 2 is for print. At the end of the CPE2 manual, it lists all processing tips for different processes. For C-41, use speed 1, for RA-4, use speed 4. If you use speed 2 to process film, you'll have to shorten procesing time. The CPE2+ has just one speed. So the film processing time should be shortened.
I believe the CPP2 instruction has similar instruction.
So film=slow speed. Print=fast speed.
See part of the CPE2 Instruction:
The manual says speed 1 for film and 2 for print, but 2 for everything if you have a lift. Either way Jobo manuals have been revised many times over the years, and in any case eventually Jobo gave up on the two speed thing for the CPE system with the use of just one speed, which is closed to speed 2 of the older CPE... The bottom line is that there is such a marginal difference if any between the two speeds when processing film i think it does not really matter.