Jobo air bells

Discussion in 'B&W: Film, Paper, Chemistry' started by jstraw, Aug 25, 2007.

  1. jstraw

    jstraw Member

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    I've done rotary processing of 120 in my Jobo twice now and the first time I got a lot of air bells.

    The second time I really increased the volume, duration and vigor of my presoak and got fewer...but not none.

    Any ideas? I'd never had air bells before this...ever.
     
  2. jp80874

    jp80874 Subscriber

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    Which Jobo, which drum or tank, which developer, how much presoak time, what temperature, what rotation speed. Could you define what you are calling air bells so we are sure we are all talking about the same thing?

    John Powers
     
  3. Photo Engineer

    Photo Engineer Subscriber

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    Prewet before development is the only answer I have seen. I wish I could say more.

    PE
     
  4. Neal

    Neal Subscriber

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    Hello Michael,

    Never had air bells in a Jobo tank. I've not developed 120 in one, but never a problem with 4x5 or 35mm. I never use a presoak and have only used Xtol and T-Max in a Jobo tank. It seems odd to me that you've increased the vigor of the presoak as that would seem to be controlled by the processor. Does your water softener need salt? ;>)

    Neal Wydra
     
  5. Clueless

    Clueless Member

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    What do you use between the developer and the fix?
     
  6. Photo Engineer

    Photo Engineer Subscriber

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    The treatment between the developer and the fix is irrelevant in this case.

    PE
     
  7. Kino

    Kino Member

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    Is it a new machine?

    Any possibility there might need be some sort of lubricant or oil in the path that would cause strong surface tension in the water if it is contaminated by the substance? Even with a prebath, it could settle on the film and make it harder to sheet, rather than spot.

    I'd pour a gallon or two of hot water with a few drops of photoflo or a mild detergent down chemical chute and then rinse with equally hot water -- assuming it is a CPE or variant.

    Might flush something out.

    My guess...
     
  8. jstraw

    jstraw Member

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    I'm using a second hand 2500 drum on a Unicolor motor. I'm filling it full with water, banging it on the bottom of the sink, agitating for 30 seconds then 10 of every minute for three minutes. I'm pouring out the stained water, refilling it, agitating for another 15 seconds and pouring that water out.

    Then I pour in my 640ml of 510-Pyro for 5 minutes of rotary development.

    That's poured out and a water fix for 60 seconds is followed by 640ml of TF4 for four minutes of rotary fixing. Then it's wash, rinse and hang to dry.

    The air bells are (very) small voids in the emulsion that appear perfectly round and clear under magnification.
     
  9. jstraw

    jstraw Member

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    I think I will give this a try. The reduction in bells between the two batches may indicate that some contaminant is being reduced each time.
     
  10. Nick Zentena

    Nick Zentena Member

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    Are other people doing all that banging? I figure with all the rotation there is plenty movement already. The only time I have a problem is when I do something stupid with loading and end up with things touching. Say not getting all the tape off.
     
  11. Ole

    Ole Moderator Staff Member Moderator

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    I've done 35mm, 120, and LF in 25xx tanks; both B&W and E6, and I've never seen any evidence of airbells!

    I don't do the banging either, but I always use a pre-wash.
     
  12. jstraw

    jstraw Member

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    I give it a bang when I first put the water bath in to dislodge air bubble.