B&W: Film Roller/Unicolor/Agitator

Discussion in 'Darkroom Developing and Printing' started by Jeph, May 19, 2006.

  1. Jeph

    Jeph Guest

    At school when I need to leave my developing film somewhat unattended I
    rig up a unicolor roller to accept our tanks. It's supposed to do
    Foward-Reverse, but it just goes in one direction. I get good results
    with it, even if the tank gets a snag for a minute or two i just add
    some time onto that process to ensure "even" results. I know the B&W
    process doesn't need to be constantly agitated, and to some extend I
    think the silver halides need to sit? Not sure, but, my film comes out
    contrasty and as expected with manual agitation.

    Is it okay to use an agitator (film roller) with B&W chemistry?
    [Forward/Forward-Reverse]

    Thanks,
    Jeff
     
    Jeph, May 19, 2006
    #1
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  2. Jeph

    Rob Novak Guest

    Yes, people use rotary/roller processors all the time with B&W. It's
    not so much that the film _needs_ to sit unagitated, but that dev
    charts are typically calculated for manual/periodic agitation.

    When manually agitating your tanks, the developer nearest the film
    surface will exhaust, and is then whisked away the next time you
    invert. With a rotary processor, you're always keeping fresh
    developer on the emulsion, so it doesn't take as long. When using
    constant agitation, decrease chart times 10-15%. You'll need to
    experiment to determine what provides the best results with your
    setup.
     
    Rob Novak, May 19, 2006
    #2
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  3. Jeph

    Mike King Guest

    I've used a Uniroller system for many years at home and processed
    commercially with a couple of different rotary rigs at various jobs. Rotary
    film processing just plain works. I personally like the reversing action of
    the Unicolor base though I'm not sure it's completely necessary, in my mind
    I feel it's better to break up surge. (There's a switch arrangement in the
    box that regulates the reversal, perhaps it's repairable?) The reversing
    action is really only "needed" when doing paper in a tube. When doing paper
    in a tube on my old Simmard-type base I would manually flop the tube end for
    end every few rotations to simulate the tube-reversal from a Uni-roller.

    Some developer rotation combinations are not so good, my first rotary
    experience was with an Imagemaker, high speed, one way rotation, no presoak
    and D-76 caused all kinds of grief. I switched the lab over to HC-110 (at a
    non-standard 1+9 as I recall) and the surge marks, etc. went away. But I
    didn't like the short developer times so finally said to hell with it and
    processed the b&w by hand while continuing to use the Imakemaker to process
    40+ rolls of 'chrome (process E-6/4--E-6 developers and E-4 Bleach and Fix,
    recommended at that time by King Concept for low volume users since the
    bleach didn't need aeration) for some time.
     
    Mike King, May 19, 2006
    #3
  4. It should work OK. Development time will have to be
    adjusted for the continuous agitation. Kodak and others have
    drum times, or, liu of these, use tray times.
    I use a Unicolor drum for large format and find that I get
    directional "bromide" streaks unless I take the drum off and
    agitate it sideways occasionally. This effect may not happen
    with tanks with reels. Reversing the direction may also cure
    some directional effects if you get them.
     
    Richard Knoppow, May 19, 2006
    #4
  5. Jeph

    joe mama Guest

    been doing it for years. just adjust for contrast, and maybe give a side to
    side manual slosh once a minute.
     
    joe mama, May 20, 2006
    #5
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