View Full Version : Developing 8x10 sheet film in JOBO CPE processor?
I recently acquired a Toyo 8x10 Field camera and should now start to develop my negatives. Up to now, I have been using the JOBO CPE processor with 2500 series drums with good result. How to do with the 8x10 film sheets without spending an exorbitant amount of money on the larger JOBO processors and Expert Drums. It se ems to me that the 2800 print drum series could be put to service. Drum 2830 tak es two 8x10 prints for developing by JOBO specifications. (a) Has anyone tried t o proceed along this track. (b) Can the sheet film be set precisely into the ree ls of the drum and will it stay there during developing? (c) Does the drum hold enough liquid to provide appropriate developing for two sheets of film? (d) Does this approach provide even developing? (e) What about the coating on the back o f the film. Will it be desolved during processing, although the film is with its back to the drum walls? (f) If not, how to get rid of the coating after taking the film out of the drum? (g) Are there other drum processing systems, cheap and not necessarily with temperature control, that do the job better than JOBO CPE?
Alas, a lot of questions! But if there are good answers to all of them, I will b e able to save a lot of money I could spend on lenses instead of on larger JOBO processors and drums; and so would a lot of other 8x10 enthusiasts, come to thin k of it.
I use a 2830 Jobo drum on my Bessler roller base. the 2830 holds two sheets of 8 X10, and calls for 100 ml of solution, I use 200 ml, just to be on the safe side . On the roller it gives very even agitation. There are no reels to deal with, t he sheets go between rails and have stayed in place without moving (I have done 50 or 60 sheets so far with this set up). The only down side to this type of pro cessing is that the backing doesn't always come off in the developer and the fix . It leaves patches on the base side of the sheet that can be removed in fixer, with a little extra agitation. I fix in the drum for 3 minutes and in a tray for two more. I use the balls of my finger tips and gently rub the back of the prin t until the dye is removed, maybe 30 or 40 seconds. Fresh fixer seems to remove 100% of the stain, and if the fixer is not so fresh, a little blueish stain will remain, but it has yet to have an effect on the final print. I'm not saying it won't, just that I haven't had a problem, yet. FYI, the BZTS system covers this same topic in about the same manner. Cleaning the drum between developments is s traight forward and relatively quick. The drum isn't that expensive, and might b e worth a try.
I'm new to large format. I tried the developing method suggested in this thread with the JOBO 2830 drum for two TMAX 100 8x10 negatives, last night for the firs t time. (Actually the first 8x10 negatives I ever developed.) I used TMAX develo per and hand rolled the drum in a pan of water. The water probably didn't help t hat much keeping the temperature steady since I didn't have water running in the pan (pan too big for small kitchen sink), but it buoyed the tank a little bit a nd helped keep it spinning smoothly once I figured out the best angle to turn at , etc. I used 30 oz. of solutions. Worked like a charm. No problem with the emul sion on the film back, perhaps because I used fresh fix as suggested in one of t he messages. I can't wait to see the contact prints, but the negatives look pret ty good. I can't see any unevenness on the negative, or any apparent problems. The 2380 drum costs $39, as opposed to the expert drum which is around $200. Of course, the 2380 is two negs at a time, the expert drum is 6 negs at a time. It took my pea-sized brain a few minutes to figure out how to fill the tank (you ha ve to tip it so the solution flows over the lip of the cup at the top of the tan k....). Also, it takes a while to fill up and empty (even once you've figured ou t how), so that has to figure in the development time somehow. But I guess that' s what testing is for, to figure those things out. I was really suprised at the great results, tho, since I was guestimating development time. Beginner's luck, I guess. Thanks for the info on how to do this, it really helped me out.
I would like to thank the two contributors for their excellent advice and for sharing their experiences with me. After giving this matter some more thought I decided that I would have to bite the bullet, after all, and go for the CPA-2 processor. It arrived at my home yesterday and I will start processing my backlong of 20 something 8x10 negatives next week. I will let you know of the results.
With many thanks Emil
Always missing it by several years but what happen? I guess because it is a CPA-2 it should be ok but if it is CPE as in the question, it might be quite different. My experience is that it is not consistent. Some good some bad. E6 is a major issue. Still struggle and in fact just holding a CPA-2 myself.
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