Rotary processing 35 mm with a print drum

Discussion in 'B&W: Film, Paper, Chemistry' started by pschauss, Oct 13, 2009.

  1. pschauss

    pschauss Member

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    Has anyone here tried this?

    I have a unidirectional motor base and a print drum which is just a bit larger in diameter than my Nikor developing tank. I am already using this setup to provide agitation for the fixing step and am now thinking about trying it for developing.

    Will this provide too much agitation compared to inverting the tank for five seconds every minute?

    Will I need need to adjust my processing time significantly?
     
  2. pentaxuser

    pentaxuser Subscriber

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    Assuming a tank inside a tank will rotate properly( I'd want to fix it in so it didn't just wobble about) then Ilford recommend 15-20% reduction. Most developers will be OK for rotary processing. If you pre-wet the film then according to John Tilsley who wrote a book about rotary processing this avoids the need to change development times. He stuck to Ilford times with total success.

    The only other difference is that a Jobo processor rotates in a forward and reverse cycle every few seconds and not the same direction all the time which I think yours will. This may give problems but I just don't know.

    Personally I'd stick to hand inversion rotation on the "better the devil you know" rather than experiment but I am cautious by nature. I wouldn't risk any film where you have negatives which are once in a lifetime shots on the film.

    pentaxuser
     
  3. MattKing

    MattKing Subscriber

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    I have been experimenting with this exact method, and it seems to be working well.

    The extra agitation does make a difference, so I use both a pre-soak and more dilute developer to compensate (I'm currently using HC110 dilution E).

    I've made a point of reversing the rotation regularly.

    6 minutes at 20C seems to work for Plus-X in HC110 dilution E (5ml of concentrate per roll):wink:

    Be careful to make sure that the tank and drum don't wander and topple:sad:

    Matt
     
    Last edited by a moderator: Oct 13, 2009
  4. johnnywalker

    johnnywalker Subscriber

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    I've done it for a while with 35mm, then recently with 120, both with Paterson tanks and reels. The 120 was unevenly developed, and on going back and checking my 35mm, those rolls also had some areas with uneven development, although to a lesser extent. Apparently the problem is that the reels might not be rotating with the tank. For the little bit of effort it saves, I'm going back to intermittent agitation.
     
  5. MattKing

    MattKing Subscriber

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    I'm pretty confident that I'm getting even agitation, but at least part of my confidence flows from the fact that my solution volumes for the developer are about 1/2 of what I would use if I was using inversion agitation.

    In addition, I'm using Hewes stainless steel reels.

    I can forsee that Paterson plastic reels may behave differently, due to the large central core.

    Matt