Rotary Processing: Ilford DD-X Volumes

Discussion in 'Darkroom Developing and Printing' started by Rob Novak, Oct 2, 2005.

  1. Rob Novak

    Rob Novak Guest

    I had been taught standard inversion small-tank processing a long time
    back, and am recently returning to self-processing black and white
    films. This time, though, it's with a Jobo rotary processor.

    I had always used 250-300ml per roll of developer (whatever would
    cover the reels in the tank), but the Jobo docs and conventional
    wisdom prescribe a smaller chemical volume in rotary tanks (the 2523
    tank I use most often has a minimum of 270ml). Looking at Ilford's
    PDF on their liquid concentrates, they say that a liter of DD-X can
    process up to 10 135-36 rolls, with developing time increasing by 10%
    per roll. From this, I deduce that each roll effectively consumes the
    capacity of 1/10 of a liter, or 100ml, with the extra time caused by
    the inhibition to development caused by reaction byproducts. So far,
    so good - I think. Ilford doesn't explicitly state the film area
    capacity of their formulations, so I'm guessing a bit.

    I know I should just shoot some test rolls of a properly exposed
    subject and dunk'em, but I hate wasting two full rolls of film if I
    don't have to. So - if I rotary process 2x135-36 rolls in 300ml of
    DD-X, do I have to make any time adjustments. More importantly - am I
    mad just for asking?
    Rob Novak, Oct 2, 2005
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  2. Rob Novak

    Nick Zentena Guest

    No you're not mad for asking. But you're missing the the trees. The bigger
    issue is the constant rotation. Odds are you'll have to cut the development
    time to compensate. How much? You'll have to test.

    Nick Zentena, Oct 2, 2005
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  3. Rob Novak

    Rob Novak Guest

    I've been holding to 20C temps and decreasing development time by
    about 15% from Ilford's dev charts to compensate for constant
    agitation when using DD-X. That's worked well for me. I get good
    tonality without excessive density with Delta100, HP5 and Pan-F so
    far. I started with Ilford's recommended 10% reduction, but was
    getting slightly blown highlights.

    I've got a few dozen rolls under my belt with this setup, but I've
    been souping them in inversion quantities - usually 600ml for two
    rolls and 300ml for a single. I think (and have been led to believe)
    that such a volume is unnecessary, but I haven't been able to get a
    straight answer yet as to the necessity of any time compensation when
    using a lower volume. I should be able to use a straight 300ml volume
    for the 2523 tanks and leave it at that.

    From reading others' experiments with the same thing, I don't believe
    I have to compensate, but no-one's come flat out and stated such
    anywhere. Maybe I should just run this afternoon's batch with 300ml
    of DD-X at my normal times and see what I get. Or maybe I should just
    throw a couple rolls of HP5 through the F4 at maximum motordrive speed
    and just process them to get my answer.

    Thanks for your help.
    Rob Novak, Oct 2, 2005
  4. Rob Novak

    Rob Novak Guest

    Well, I answered my question - I shot two test rolls of two subjects
    with a fairly full range of tones, and processed them in 300ml of DD-X
    1+4. Negs look fine out of the rinse. I'll loupe them when they're
    done drying, however they don't seem to have density issues.
    Rob Novak, Oct 2, 2005
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