tray developing times vs. rotary processor times

Discussion in 'B&W: Film, Paper, Chemistry' started by jnanian, Sep 11, 2005.

  1. jnanian

    jnanian Advertiser Advertiser

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    hi

    finally i have loaded up my rotary processor to develop a bunch of 4x5 sheet film ... but my problem is that i usually develop in trays ( don't stop shuffling the film until the time is up ) ... would it be in the right ballpark if i use the same time in my rotary processor as i do in trays ... or is there something i might be missing here ?

    thanks in advance for your suggestions.

    - john
     
  2. Jorge

    Jorge Inactive

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    I suppose the rotary will be constant agitation, so take off about 30% of your usual time from tray developing. Should get you in the ball park, but you know you are stuck with some testing, right?
     
  3. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    I'd have said to take off more like 20%, but 15-30% somewhere in there should be a good starting point. In theory, both are "constant agitation" but rotary drums are a little more constant than trays, since each sheet is constantly being agitated, and not sitting in the stack for part of the time. Of course that can vary for tray agitation if you sometimes develop 2 sheets and sometimes 10 sheets in a stack, so I usually try to keep track of tray agitation in terms of how often I should cycle through the stack (e.g. 1 cycle every 30 sec or 1 cycle every 15 sec. or constant cycling).
     
  4. lee

    lee Member

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    according to the old JOBO USA website a 5 min pre wash allows you to use the same times used previously for trays. That said I would not hesatate to run a test to verify this info.

    lee\c
     
  5. jnanian

    jnanian Advertiser Advertiser

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    thanks guys!

    ( and les )

    i appreciate your help ---

    - john