JOBO (CPE-2) - rotation speed for films question

[dave92270]

Hello,

 

Some time ago I purchased old Jobo CPE-2 (model #4060, non-plus

version) from the local camera store and it was a very good deal -

there was only a single crack in the tub which I patched easily. The

only remaining problem is the rotation speed "1" (slow one, for

films); the rotation usually stalls after a short while. Either the

motor unit is bad or gears on the lift are worn.. I developed only

one batch of 35mm films in C-41 at "1" speed (had to help the

rotation by hand time to time in order to finish the run) and gave up

on film processing until I'd fix it. Those two 35mm color rolls

developed at "1" slow speed turned out very nice.

 

Anyway, the "2" speed (fast setting for papers, about 75rpm, with

auto-reversal functional) is working fine, and I successfully process

RA-4 prints in the unit. I wonder whether it is possible to process

film at this fast setting without being overly high contrast or

showing other undesirable effects. I did some reading at Jobo website

and it seems that CPE-2Plus (new) model has only one speed for both

paper and film, which corresponds to "2" (approx. 75rpm) speed on my

old CPE-2. Jobo also insists that this fast rotation is suitable for

both papers and films. Can anyone advice on this?

 

I need to process both B&W and color films, and in all formats

including the sheet film. I'll probably go ahead, shoot a few 35mm

test rolls both B&W and color, and run it through at high speed

setting to find out, but if anyone could comment on this topic I'd

appreciate. I need to purchase 2500 series tanks with sheet film

reels as well, and don't want to spend $$$ unless I know for sure

that the high speed setting is fully suitable for film development.

 

Thanks for advice in advance.

 

(I hope that I picked a correct forum for this post)

 

Dave

[rowland_mowrey]

Dave;

 

Jobo currently recommends using the faster "P" setting or paper setting for film as well.

 

Ron Mowrey

[georg_kern]

With paper, the speed should not be that critical. However, with film I had the experience that slow speed easily leads to "streaks" or "lines" of uneven development on the film (especially with 120 format). The developer might be better "mixed" at high speed, while developer exchange between inside and outside of the spiral is insufficient at slow speeds. BTW, I have changed back to inversion agitation anyway (for both b&w and color).

 

Regards

 

Georg

[robert_dermer]

Dave,

I just ran my first rolls and sheets of film through my CPE-2 (non- plus unit and patched cracks as well!) this past weekend. I didn't try the slower setting at all since Jobo had seen fit to discontinue this option on the newer model. I also had the stalling problem but only when using a 2500 series tank; using the 1500 series tank for 120 went smooth as silk. During the 4x5 (2500 series) run I had to stop and restart the motor several times during developer but it ran smoothly through the rest of the process.

 

What I think was the problem is that placement of the tube rollers when using 2500 series puts one roller in close proximity to the bottle rack and there may have been some scrubbing going on. I didn't notice that until after I had finished the process so will have to check it closer next time.

 

Thankfully all the negatives came out fine. I hadn't processed film in 15 years and had completely forgotten the smell of B&W fixer. the first whiff put a smile on my face and I had to run and get the wife saying "remember this?"

[rowland_mowrey]

Robert;

 

If the rollers drag on the side of the Jobo with the 2500 series tanks, you probably have the rollers installed incorrectly.

 

With the 1500 series, there is a standoff that holds the rollers and faces inwards toward the tank. With the 3000 series, the standoff faces outward toward the sides of the Jobo. On some Jobos the roller can rub or the 3000 drum can rub. With 2000 series drums, the standoff is not used and is attached directly to the cross brace on the lift. It is about 2 inches or 4 cm from the sides of the Jobo and therefore cannot rub at all. The drum also clears the sides of the Jobo with the 2000 series.

 

Check your manual for a drawing of these 3 configurations and make sure you are using the correct one for your tank.

 

Also, there is an extension cross brace that goes on the center part of the water bath across the ridges. With some tanks, it is necessary to use an extra set of rollers (and braces depending on drum used) for support. Also, the position of the rollers and cross braces should be adjusted for maximum support.

 

I have been using Jobos for about 20 years (or whenever they first came out) and have never had a problem. I have 2 of them.

 

Ron Mowrey

[dave92270]

Thank you guys all for commenting on this - it looks like that higher speed could be suitable then...

 

Until now, I've been developing all my films mostly at room temperature in inversion tanks and trays (usually around 80F), which shortens B&W processing times up to 40% for developers which I use. Since inversion tank development times will be further shortened due to continuous rotary processing, the films could come out not too high contrast because the relatively short time spent in the developer. On the other hand, for color film processing I can raise the temperature to over 100F, so I will not need to develop film for 14-15 minutes (C-41 @ 80F); if development is only 3.5min @ 104F or so, the increased agitation should have negligible impact on overall contrast.

 

I shot a color test roll yesterday and will develop it today at high speed setting, and going to shoot B&W roll test roll today as well - I'm getting pretty confident now that all will be OK.

 

Thanks again for your information.

 

Regards

Dave

[rowland_mowrey]

Dave;

 

C41 is 3 min 15 sec at 100 deg F. I use that with EK kits on my Jobo at the "P" setting and match lab results exactly.

 

Ron Mowrey

[kevin_jesequel]

The ony thing Jobo still recomends the slower speed for is Ilfochrome processing.

[rowland_mowrey]

Kevin;

 

Any relation to Pierre Henri Jesequel?

 

Ron Mowrey

[dave92270]

I developed a test roll of FujiSuperG+100 for 4 minutes@104F (because I've been reusing my C-41 chemistry for a while, I gave it a little longer time; I use Arista C-41 kits with listed time/temp 3:30 min @ 104F for fresh mix) - it came out nice; no problem with contrast or anything else - the high rotation speed is fine...

 

I'm not planning Ilfochrome/Cibachrome anytime soon (if ever), so I'll work with CPE-2 at high speed only. Now I can buy sheet film reels and more drums without any fear of developement problems.

 

Thanks for input to everyone, all turned out well.

 

Regards

Dave

[robert_dermer]

Rowland, thanks. I will check roller placement again.