Jobo Expert Drum and uneven processing.

Discussion in 'Darkroom Equipment' started by chrobry, May 1, 2006.

  1. chrobry

    chrobry Member

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    I am using Jobo Expert Drum for 4x5 processing. Often I have the problem with uneven processing. There are areas on the bottom part of the negative, usually right next to the edge, which seems to receieve no chemistry. Strikingly, sometimes they clearly received developer but did not get the fixer. I always load the film dry, then prewet for two minutes and proceed to processing. I use the drum on unicolor roller. I will appreciate any advice to solve this pretty frustrating issue.
    Jan
     
  2. TheFlyingCamera

    TheFlyingCamera Membership Council Council

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    First, which Expert drum are you using? If you are having problems with the film not getting chemistry, my first suspicion is that the Unicolor motor base is not level, therefore chemical distribution is uneven. However, when you say that certain edges are not getting chems, that makes me wonder if you are loading the film properly. Post an image of the improperly developed film, and shoot a pic of yourself loading an already-developed negative in the drum so we can see what you're doing right or wrong. The Expert drums, properly used, should give you perfectly even development. Another question for you then is also, how much chemistry are you using, and how many sheets at one time?
     
  3. hka

    hka Member

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    It seems that the Expert Drum is rotating in just one directions instead of changing it after three or four turns??
     
  4. chrobry

    chrobry Member

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    this is 3010 drum. I load up to six negatives, always one per tube. The drum is leveled as much as I can do, I can not exclude small imbalance. The developer volume is 300-350 ml, I usually use more of the fixer, up to 500 ml. The "unaffected" negatives are indeed very evenly developed.
    The drum is indeed rotating in only one direction. I posted the same question to another forum and just got the advice to change the direction by flipping the drum manually. I will do that.
    I will post a scan of an affected negative and a picture of how I do load the drum this evening. I do not have negatives and drum with me now.
     
  5. lee

    lee Member

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    I would add more chems also the 3010 will hold about a liter I think I would increase the amount of pre wash and extend the time out to about 5 minutes.

    maybe the method of getting the chemicals into the tank is at fault also That has always been my beef with the expert drums on non-JOBO.

    lee\c
     
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  6. chrobry

    chrobry Member

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    I am sorry - I was wrong. It is 3006 drum. Not a 3010.
     
  7. Lopaka

    Lopaka Member

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    When I got my Jobo and all the drums/reels etc that came with the deal, I was puzzled by how the chemistry got distributed among the different compartments in the expert drums. Then I noted that Jobo syas the expert drums must be used with the lift attachment - the chemistry is poured through the lift funnel, meaning the drum is in the horizontal position and rotating while the chemistry is poured in. That's the only real difference I can see using a Jobo with or without the lift - so the method of adding the chemistry may be a key.

    My guess, based on above.

    Bob
     
  8. jeroldharter

    jeroldharter Member

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    I agree with the others:

    make sure the processor is level in both directions

    set the little white thing so tthat the drum rotates in both directions

    make sure you have the proper water level in the upper compartment -too much and the drum floats and becomes unlevel

    use a 5 minute water pre-soak

    use at least 500 ml of chemistry
     
  9. lee

    lee Member

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    he is not using a jobo he stated in his first post he is using a Unicolor motor base.

    lee\c
     
  10. jeroldharter

    jeroldharter Member

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    Sorry. Never mind then.
     
  11. lee

    lee Member

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    Jerold,

    I just re read my post and I did not mean it to sound so harsh. Forgive me pls.

    lee\c
     
  12. jeroldharter

    jeroldharter Member

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    No problem with me. I skimmed the post and did not catch the most relevant part.
     
  13. chrobry

    chrobry Member

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    I scanned the affcted negative. Here is my problem. Also here is how I do load the film. I must admit, however, I did not pay too much attention to how deep in push the film into the tube. Sometimes the film edge was not exactly parallel to the edge of the tube. I posted the same question to largeformatphotograpy.net forum and got the advice that this may be crucial, which I did not realize. So sometimes my film was certainly loaded not exactly as shown.
     

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  14. TheFlyingCamera

    TheFlyingCamera Membership Council Council

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    well, looking at your negative example, the perfectly clear edge with the even line looks like it is supposed to look. If you are getting that inconsistently, I'd check your method for loading your sheet film holders for consistency. The wierd blob on the negative looks like some kind of developer drip. That could be caused by either the filling method (since it is an Expert drum being used off a Jobo processor, you'll have that issue with filling while the drum is not rotating) or you aren't cleaning your drum carefully enough between batches, and the film is sticking to the wall of the drum and trapping chemistry between it and the drum wall, causing the overdevelopment spot. You need to double-check to make sure you are loading the film in the drum emulsion side IN, not out.
     
  15. EKeck

    EKeck Member

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    Loading an Expert Drum

    Definitely what has been said makes sense ( especially facing the emulsion the correct way ). Here's a snapshot regarding loading the film - pushing the film too far in can cause negatives not to clear properly. While the photo here shows a 3010, it could be the same issue for the 3006.
     

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  16. boyooso

    boyooso Member

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    more ideas

    Could it be that the rotation is too fast and shifting the film so that during one stage of processing the film is in one posisiton and another stage it is in a different position which prevents it from getting chemistry?

    I can't remember what the actual speed is for the 50 setting on the jobo (the proper setting for expert drums), but I bet it is 50 rotations per minute (maybe someone else remembers)

    Or the rotaion could be too slow, thus not distributing the chemicals through those tight spots in the expert drum sufficently.

    Or it could be somehow related to how you pour each chemical into the drum? That would certainly accout for consistency issues. Also, how long is each chemical in the drum. Because of unexplainable problems I've moved to 2 minutes of stop bath and had no problems since????

    I would try and use more chemicals...

    Also, I would appreciate a scan of the entire peice of film, I can't even tell what the problem is from the picture you uploaded.

    I hope this helps, but I'd love to see the whole piece of film.

    Corey
     
  17. colrehogan

    colrehogan Member

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    Looking at the negative example, it looks to me like perhaps the tube wasn't properly dried prior to putting in the film.

    FWIW, I use all my Jobos with a Unicolor drum and take the drum off the rollers when changing chemicals. This is because I don't do my developing in a bathroom. I've typically been doing it where I have access to a tv/computer and I don't want a mess from the chems if I can help it. I think maybe I've had problems with some swirl marks on possibly one neg (haven't printed/had it printed so I can't be sure) in the last couple of years (knock on wood). :wink: I don't load the Jobo completely with film though either.
     
  18. chrobry

    chrobry Member

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    Thank you very much for your input. I really learned a lot from here and from the same question I posted to largeformatphotography.info forum. I think I identified following problems:
    1. accidental wrong film loading
    2. not enough chemistry added (I will increase to at least 500ml)
    3. wrong technique of drum filling

    I do not think that the problem has to do with drum drying as I usually process films only once in a week, it has enough time to dry completly. I also use the sponge to dry the tubes.
    This may well be that my setup is particulary prone for wrong film placement because the drum rotation is much slower then recommended by Jobo. Jobo recommends 50rpm and my motor base gives only 15rpm. On the other hand PyrocatHD instructions recommend much slower rotation then specified by Jobo. I think that combination of above factors actually causes my problem.

    BTW - do you think that increasing the pyro developer volume will help to decrease oxidation rate during drum processing? It seems resonable as there would be less air in the drum and also volume/surface ratio would be better.

    Once again I want to convey my apperciation for your time and help.
    Jan