B&W film in Jobo processor... starting point suggestions

I have processed my sheet film in trays for decades with great results although, sometimes when I have a very large amount of film, I process in my line sink. But I recently picked up an Jobo to process my E6 films because my nearby E6 labs have closed down. The E6 processing is going fine.

I have two batches of b&w sheet film to process today and I think I will process them in the Jobo. I almost hate to do it because if I decide to switch to Jobo processing for my b&w film, I will have to do my Zone System testing again. I just re-did my testing last year with all my film/developer combinations and I don't relish the idea of doing it again now. But I will if I decide to switch to Jobo processing with it's obvious advantages of convenience. The batches of film I have on hand to process are not important so minor processing errors wouldn't be a disaster.

I would like to get some advice from others who have switched from tray processing to rotary processing in a Jobo as to how much they found they had to adjust their developing times when switching to Jobo processing -expressed as a percentage. I have found charts giving specific development time recommendations by John Sexton and others but that isn't too useful for me because I use different developers than John. Also, when John tray-processed, his times were different than mine even when we used the same film/developer combinations, which is to be expected because of all the variables involved. So I would like to find a rule-of-thumb percentage figure that I can apply to my tray processing times to get roughly on target when I process in the Jobo - at least until I get around to doing calibration testing.

So, for example, has anyone found that they had to reduce their tray processing times by 10% (or whatever) when they switched from tray to Jobo processing? If you have a recommendation, please let me know if you are using a pre-soak because that is important to know, of course. And if you are pre-soaking, for how long? Like everything else, I have found conflicting information on pre-soaking when using a Jobo for b&w film.

It will be nice to go down and process in the light but I just want to get a decent starting point that I can use until I do real testing.

I advise students to begin by reducing their tray times by 15%.
This works for many, while others find they need to use only a 10% reduction, while others require 20%.
AS an aside, if you use a pyrocatechin, or pyrocagallol based developer I find it best to run the Jobo at as slow a speed as possible to eliminate streaks.

I let the film pre-soak for 5 minutes as recommended by Jobo. Also reduce development time by 15% as Jim has noted. Use photo-flo after you've removed the drum from the processor otherwise the rotation will create a lot of foam.
You will need to do some testing to arrive at the developing time.
It's a nice system - enjoy it.

The JOBO Quarterly had multiple articles on using the processors, including rotation speeds, presoaking, and adjustments from small tank times. I don't recall anything about adjustments from sheet film in trays, but it would be hard to establish a standard for tray development anyway.

The Quarterlies are well worth a look though:

Dead Link Removed

Lee

I presoak at the "f" speed for 1 1/2 minutes and develop normally except I do reduce the developer time by 10%. It use HP5 with D76 and HC-110 at 68 degrees with no problem in a jobo 3005 drum. My 4x5 stuff turn out great as does the 120.

My Jobo is a CPE2+ with lift that has one speed -- 75 rpm.
I use a 3-5 min rolling pre soak with water and manufacturers time minus 15% for N development. FotoFlo is good but I never use it in the drums but in a dish/tray.

I use an ATL-1500 which has a fixed speed. I have found, similar to the others here, that a 15-20% reduction in "small tank" times is required; where "rotary processing" times are posted, I need around a 5% time reduction. I use a 5-minute presoak, which may shorten times by allowing somewhat easier entry of developer into the emulsion (or so I've heard it explained.)

It really takes the tedium out of processing film, IMO.

Good Afternoon, ZoneIII,

Since the effect of rotary processing is highly similar to tray processing (continuous agitation in each case), the times should be either identical or close to that. When I switched to drum processing from trays several decades ago, I believe that I simply continued to use the same times and noticed no difference in result. I regard drum processing as simply a no-hassle, no-scratch, virtually fool-proof variation on tray processing. I presoak, using a Chromega drum and a unidirectional, single-speed motor base.

Konical

I never did do tray development for enough time to get a time /temp down for it, but I have been using the Massive Dev Chart's (http://www.digitaltruth.com) starting times as listed, with my Jobo set to the slowest possible speed (below F, just before the click to turn it off). I use the Ilford wash sequence in the drum (4,3,2,2 minutes) while still running on the machine, then I take out the film and manually dunk it in the Photo-Flo. I do a three minute pre-wash in the Jobo.

Thanks for replies, folks. That's very helpful and it confirms my thoughts that development times should probably be reduced due to the continuous agitation of rotary processing.

Lee: I may not explained myself clearly. I'm not trying to establish a standard for tray processing. I already have that. What I was looking for was feedback from people who have switched from tray processing to rotary processing to find out, in general, if they had to reduce their development times when making the switch and, if so, by about what percentage. The responses posted here are just about what I expected them to be.

Konical: Actually, tray processing is not continuous. I have always cycled though the stack once every 30 seconds so agitation is intermittent. For that reason, I expected (and wasn't surprised) to get responses recommending a reduction in development times to compensate for the continuous agitation of rotary processing.

However, before I came back to read the responses here, I read all the information in the Jobo manual that came with the processor that I had missed before. It recommends that you start using your normal development times that you used with intermittent agitation. Presumably, the pre-soak compensates for that. So I went ahead and processed one batch of Kodak Tmax100 sheet film in my 3010 tank using my normal tray processing time of 5 minutes in HC110-B for N development. I gave a pre-soak of 5 minutes. I just took the film out of the drier and it looks pretty good, actually, although it's really difficult to tell until I make proofs. But it looks pretty much like my tray processed N films. Contrast may be slightly higher... maybe N + 1/2 or so, based on a visual inspection, which isn't reliable, of course. As you know, Tmax100 has a reputation for being very sensitive to development variations but what many people may not know is that it is very INsensitive in HC110. In fact, it's far less sensitive to changes in development time than TRI-X is in HC110-B! N+ times are very long with this combination which gives great control over contrast. But when I want great expansion or contraction with this combination, I use other methods including dilute developer, selenium toning, etc. Everyone has their favorite developer for this film. John Sexton uses D76, I believe. I have tried all the main developers with it and, for me, HC110 is the best although haven't worked with Tmax100 and Pyro extensively so I can't comment on that. It was too much of a pain to agitate the slippery films in Pyro with surgical gloves on but it should be a breeze with the Jobo so I will probably give it another try.

Now I have a batch of TRI-X to process. Since it's not important film, I'm going to go ahead and process it with my normal tray processing time. My normal time is only 4 minutes so, if I wanted to reduce development, I would dilute the developer. But I'll just go ahead and use a pre-soak for this unimportant batch and my regular development time and see what happens.

ZoneIII said:

Lee: I may not explained myself clearly. I'm not trying to establish a standard for tray processing. I already have that. What I was looking for was feedback from people who have switched from tray processing to rotary processing to find out, in general, if they had to reduce their development times when making the switch and, if so, by about what percentage.

Click to expand...

I understood what you were trying to do. I don't recall adjustment "from sheet film in trays", meaning going from that to JOBO processors, being mentioned in the JOBO Quarterlies. My statement about establishing standard tray development is meant to indicate that JOBO would have a difficult time establishing a standard for tray processing from which to suggest departures when going to the JOBO. Few people would tray process just alike because of variables on the number of sheets, speed of shuffling, etc, so specific suggested adjustments based on adjusted tray development times would be hard to make worthwhile.

My main point is that if you're just starting with the JOBO, there's lots of good info in the Quarterlies that you won't necessarily see in the instructions, even if you have them. JOBO instructions also changed in several important ways over the years, and you can track those and the reasons for them in the Quarterlies. Many of the suggestions you've seen in this thread are also drawn from or identical to suggestions in the JOBO Quarterlies.

Lee

The data sheet for your film or the instructions for the processor may give you a suggestion. Like everything else in photography, it'll have to be determined by a series of tests, but there are starting points suggested by Kodak (reduce tray times by 15% to start, I believe).

Personally I find that HC-110 at "full strength", or Dilution B, si too storng, and it will "burn" your film in the sense you loose the subtleties in the shadows, highlights, etc.. Here's my setup that works for me. You mileage WILL vary, so take with proverbial grain of salt and do what works best for you, but feel free ot use my setup as a base for experimentaiton on your own.

Jobo 2551 tank, two 4x5" reels that hold a total of 12 sheets. However I only do 8 sheets at a time on both reels.
Non-Jobo motorized base, one is Unicolour. hand rolling works too if you go back & forth.

I use mostly HP5+ or Tri-X. I always expose my film at 200 ISO/ASA using a spot meter (pentax, analog)

Pre-soak in tap water for 4-5 minutes, near 20C / 68F. Standing, not moving. If rotating, use a water soak around 3-4 minutes.

At 20C or 68F, I mix 10 ml of pure HC-110 syrup in 650 ml of distilled water. THis is about HALF the Dilution B strength.

All other developing is in tap water, but regardless of developer, I always use distilled or filtered water for the developer.

Constant rotation on the roller base. Development times vary, depending on you N -1, N+1, etc, but a starting time is between 9 to 10 minutes. I used to have an older diffuse head enlarger, and I found I had to develop my negatives a bit "harder" so I always started with the 10 minute mark, but now I use a 504 DeVere I use 9 minutes as a starting point.

Dump, tap water wash, then I use a NON hardening fixer like Hypam, constant rotation for about 3-4 minutes. While I re-use my fixer for a week , my developer is always fresh, always one shot. Afterwards wash ,, etc, as per normal.

This works great for me, but agian, you mileage will, not MIGHT, but WILL vary, so experiment on your own and see what works best.


good luck, have fun

If you use CLAYTON F76 plus Developer, i have those times already charted.