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Thread: Improving agitation in hand-rolling Jobo tanks, specific to materials

  1. #1
    Yes, but why? David R Munson's Avatar
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    Improving agitation in hand-rolling Jobo tanks, specific to materials

    I already searched the archives and didn't find out exactly what I wanted to know, at least specific to my materials, so I thought I'd post a question. Anyway, my photo professor this quarter requested that the members of the class switch to some kind of tank or tube for processing film this quarter. Because I intend on buying a Jobo processor for doing my roll, 4x5, and color stuff in the next year or two, I went for a Jobo tank instead of trying to dig up an old Unicolor or Omega drum. Can't afford an Expert drum at this point, though, so I bought the 2509N 4x5" reel and the appropriate tank to hold it. In my preliminary test (singular) I found agitation to be fairly consistent, but not completely. This spawned some questions. I searched the archives, read many an old post, and still have these questions:

    1. Rotation speed: posts have indicated rotation speeds from 35-75 RPM, both extremes indicated as giving even development. Do the pysics of it all point to one end or the other?

    2. Ratio of rotation and reversal. Would the number of rotations in any given direction prior to reversal of direction affect consistency of agitation? This assumes equal number of rotations in every cycle.

    3. Developer. I currently develop in HC-110 Dilution B, my film being TMax 100. I like the results I get with HC-110 tray processing, so that's why I'm using it with the drum. However, would choice of developer affect how even development is? Would I have a better chance of getting even development if I went back to TMax RS?

    4. Presoak. I have received conflicting reports about the importance of a water presoak. I usually presoak for about 2 minutes with all my film. Any difference using the Jobo drum?

    As I stated before, the materials I am currently using are TMax 100 4x5" sheets developed in HC-110. I have TMax RS developer readily available to me. I do not currently have a Jobo processor to automate things, so I currently use the little roller base and roll by hand, though the roller base isn't ideal considering the "stubby" dimensions of the tank. I'll keep developing the important stuff in trays until I get this resolved. Any thoughts regarding the 4 questions I posed or any general suggestions for maximizing my chances of even development would be greatly appreciated. Thanks.

  2. #2

    Improving agitation in hand-rolling Jobo tanks, specific to materials

    David maybe you can afford a Beseler motor base (25 bucks on e bay). Use this and you will be fine. Before I changed to the expert drums (which I still use on the motor base) I used the same tank you bought and got very nice reuslts. just make sure you get the motor base with the revrsing feature and it will work just fine.

  3. #3

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    Improving agitation in hand-rolling Jobo tanks, specific to materials

    My procedure: I don't know if my system could be improved, but I like the results, contrast and uniformity in the developed film. I use the same drum as you; No rotation, just the same inversing system than in roll film. No presoak. Developer, with TMax100, TMax RS. Problem: I need each time 1,5 litres of solution. I don't like the roller base. I think it's so easy to be the best system... I would like to know others...

  4. #4

    Improving agitation in hand-rolling Jobo tanks, specific to materials

    Hi David,

    I have been using the same set up as you for two years. My results are consistant and development is even. By the way, the tank you have is too small to fit on the motor bases that the previous poster suggested. I slowly and smoothly (no jerking motions) rotate the tank for twenty counts one way than do the same in the other direction until the time is up. I do a two minute presoak as well, and HC-110 is also my developer of choice.

    Don't spend a whole lot of time worrying about rotation rates, just do it smoothly, and be sure whatever you do is consistant. T-max is a very sensitive. This is good, because it is easier to manipulate than other films, but it is bad, because you need to be consistant. You can get away with a lot more inconsistancies with Tri-X.

  5. #5

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    Improving agitation in hand-rolling Jobo tanks, specific to materials

    As already indicated above, the tank you have will not fit on the motor bases such as Unicolor etc.

    More specific to the questions you have asked.

    1) In my experience, the rate of rotation probably does not matter terribly. Most changes in curve shape needed fairly dramatic changes in agitation rates (for example, for a noticeable, non-significant change in curve shape, you would need to move from agitation once every minute to about once every three minutes). As far as evenness etc are concerned, I have developed sheets on a Unicolor motor base, by hand on a Jobo roller base, in a Duolab, in BTZS typr tubes. I have never really encountered any unevenness due to the agitation. Any rotary agitation process produces a fairly high agitation rate and typically that reduces unevenness.

    2) Keep in mind that the constant agitation can change curve shape (depending on what your processing regimen in trays was). If the highlights were getting a little straved between agitations in trays, that would put a mild shoulder on the film. This shoulder will be typically eliminated with the high rate of agitation in rotary processing. That said, most sheet film development in trays does not starve the highlights (unless one is consciously trying to do so by using greatly reduced agitation etc). Some developers can be quite finicky about agitation. PMK pyro is a good example and moving to rotary processing may call for some testing. With PMK pyro, the trouble appears to be excessive aeriel oxidation and is typically fixed by using double the usual amount of the A solution (i.e., the developing agent) to prevent the developer from getting exhausted.

    3) Yes, a presoak appears to affect different films in different ways (increasing contrast in some and reducing it in others - the main issue is probably the replacement of the water by the developer in the emulsion). However, as long as you test and calibrate to your regimen, you can get repeatable results. I tend to prefer a presoak when I'm using rotary agitation for the reason below.

    One thing that can produce streaking. If you're doing a series of developments and the drum and the cap isn't perfectly dried, it can create problems. I found that snapping the cap on would send a bunch of small water drops onto the surface of the film and that could create uneven results. My solution was to go to a 2 minute water presoak and that fixed the problem.

    Good luck, DJ.

  6. #6

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    Improving agitation in hand-rolling Jobo tanks, specific to materials

    I have used both the 2509n reels in the 2500 series tank and the expert 3010 on a uniroller #352 for several years. i don't know about the Besler base, but the uniroller + jobo drums+ TmaxRS or HC 110 work wll. I prefer the TmaxRs . Bob

  7. #7

    Improving agitation in hand-rolling Jobo tanks, specific to materials

    I use the 2500 series tank and reel. But I use it with Tri-X and HC- 110B, so take this for what it's worth.

    I develop with constant agitation. I roll forward 10 half turns over the course of 10 seconds or so, roll backward 10 half turns again over about 10 seconds, then invert the tank twice and slap the bottom to dislodge bubbles. I do this in a 68 degree water bath and don't have any sort of roller base. I put a finger in the "hole" on the bottom and spin the tank around that axis. Presoak 3 minutes and develop for 6 using this same pattern.

    My tank is designed for use with a lift, so I found a rubber stopper that fit. I use one liter of chemistry. That's more than necessary, but that way I know I'm not exhausting anything.

    Good luck.

    DW

  8. #8

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    Improving agitation in hand-rolling Jobo tanks, specific to materials

    David,

    I have the same set up and praise it for consistant results. Years ago I used the tray method and my results were inconsistant...plus you are in the dark for the whole procedure. I use TMAX RS developer. If I had to guess, I rotate the tank on manual rollers at about 40 rpm (judging from the time it takes to turn it one revolution). Being a dope, I didn't read about the reversal of rotation and I would lift one end of the tank 45 degrees every 20-30 seconds...I also presoaked with water for a minute. The results have always been good (now I reverse the roller instead of the 45 degree tilt and find the results are the same). A couple of months ago I shot a subject with a roll of 120 film (T-MAX 100) and 6 sheets of 4 X 5 (T-MAX 100). All were done with the same lighting and similar exposures. I developed the 120 film in my smaller JOBO tank, which I fill up and agitate once every 30 seconds for 5 seconds by inverting the tank. The 6 sheets of 4 X 5 film were developed in the large JOBO tank (like yours) on the rollers. I used the T-MAX RS developer for both tanks...all 68 degrees. The development times were in accordance with recommendations on the T-MAX RS container. The results (tonal range, density, etc.) were the SAME comparing the 120 film with 4 X 5 sheets. This led me to the conclusion that both methods will yield consistant results. I am very pleased with the JOBO tank set up for sheet film. I found tray developing to be a big pain -- --- ---! I have not used HC-110, so I have no basis for comparing it with T-MAX RS. I am glad you posted these questions, as the RPM's and pre soak had my curiousity...I will be interested in hearing somemore feedback! Take care.

    J. P. Mose

  9. #9

    Improving agitation in hand-rolling Jobo tanks, specific to materials

    Paul Mongillo:

    I have been using both the 2509 and the expert drums in a roller base for many years and I can tell you it is NOT too small for the motor base..if you havent tried it dont knock it bubba.....

  10. #10

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    Improving agitation in hand-rolling Jobo tanks, specific to materials

    Hi Jorge, not knocking anything. I have tried it and that is why I said it will not fit. I was not referring to the expert drums - I'm aware those fit on the Beseler and Unicolor motor bases. The 2509, on the other hand, is too short and does not reach across both rollers - maybe it would if you put the reel into some other drum (one of the print drums, for example) but the 2509 drum by itself certainly was way too small to just set down on the roller base. I tried this about 4 years ago, though - so maybe something has changed. Cheers, DJ.

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