Zone system in rotary processor

Discussion in 'B&W: Film, Paper, Chemistry' started by bobrb, Apr 6, 2007.

  1. bobrb

    bobrb Member

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    Hello
    I recieved Jobo procesor and I have idea to calibrate my negative process for Zone system (for a long time, but this can be motivation). Is it possible at all? Or shall I calibrate it with standard inversion?
    I thing with rotation in processor I can better standardize all parameters but I will have only one/two options for rotation speed (process dynamic)

    Second question:
    Is it possible to calibrate process priary for Fuji Acros or shall I at first test it with clasical emulsions (I use eg. FP4+ )
     
  2. Dan Henderson

    Dan Henderson Member

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    I'm not exactly sure what you are asking, but it seems to me that you should calibrate your development times with the same method you intend to use regularly. In other words, the Jobo is part of your development system, so you should calibrate with it. And I think you should calibrate each film separately. I would suspect that N+ times, for instance, would be different for FP4 and Acros.
     
  3. bobrb

    bobrb Member

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    Sorry

    primary question is: "It is possible to use ZS with rotary processor?" With it I have only small possibility to change development dynamic (agitation). Is it so important to not use rotation and stay with agitation?

    Of course, all processes (N, N+, N-) will be diferrent for different films. FP4 has smaller dynamic range and clasic emulsion (without any T or sigma crystals) --> will calibrating to ZS be easier for FP4 than for Acros
     
  4. Roger Hicks

    Roger Hicks Member

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    No reason why not. You will remove most or all of the effects of acutance developers, but with LF the importance of acutance is disputable anyway. Contant agitation will give a little bit more toe (true ISO) speed and very slightly coarser grain but again the latter shouldn't matter with LF.

    Cheers,

    R.
     
  5. bobrb

    bobrb Member

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    This is that I wanted to know.
    Becouse I use 35mm and 645 format I will not try it...
    Thanks
     
  6. Allen Friday

    Allen Friday Member

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    Yes, you can use the Jobo with the ZS. I use mine for 35, 120, and sheet film. Don't worry about the different rotation settings. Pick a slow rotation (around 70 rpm) and leave it there. The rotation will then be constant from roll to roll and film to film. Pick a temperature setting and leave it there. It will then be constant. I use 21 degrees. The exact temp is not terribly important, but it is important to use the same setting time after time. Use the same concentration of developer. If you use different developers or different dilutions, you will have to do a test for each. Once you have settled on your standard for rotation, temperature and developer, the only variable you will change will be the time of development. More time for + development, less for - development.
     
  7. phstef

    phstef Member

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    Hi Bobrb,
    Regarding the times that it uses normally you will have to diminish them of a 15% approximately.
    Stefano
     
  8. Byron Worthen

    Byron Worthen Member

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    JOBO used to have a site with articles about various things. I don't know if they still do. But John Sexton wrote a great one about using a JOBO with the zone system and I have had much success with my own negatives using that article as my "recipe".
     
  9. RalphLambrecht

    RalphLambrecht Subscriber

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    that's all i've ever used
    develop five equally exposed rolls of film for 4,5.5,8,11 an 16 minutes ,measure and plotfind some help here
    here:http://www.darkroomagic.com/DarkroomMagic/Darkroom.html
     
  10. pentaxuser

    pentaxuser Subscriber

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    Looks like we lost the OP in 2007, Ralph. He appears to have started this one thread only but at least he got the answer he wanted then when he replied in post 5 so left APUG happy.:D

    pentaxuser
     
  11. bluejeh

    bluejeh Subscriber

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    Calibrate film - Jobo processor

    I recieved Jobo procesor and I have idea to calibrate my negative process for Zone system - Bobrb

    Many thanks for your question bob, and Ralph for your timely answer. There has been so much on APUG lately which mentions this topic without adequate explanation - I need right now to understand the process of calibration from film to paper. I've downloaded the files from your website link and will walk through it. I also have truly enjoyed your book Ralph "Way Beyond Monochrome", a lot of the topics are so relevant for me today as a darkroom user. Again, thanks.