Chromega Drum and Roller base questions

Discussion in 'Darkroom Equipment' started by BenZucker, Oct 13, 2009.

  1. BenZucker

    BenZucker Member

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    I just got a Chromega drum w/ a chromega motor base. I have a few questions:

    1.)
    I see that the base I have does not switch the way it rotates. it only goes one direction. Would I want to switch my drum during development so that it rotates the other way for more even agitation? or should this not matter?

    2.)
    I plan to use this for 4x5 and 8x10 film. I know how to set it up for 4x5, but if I'm doing 8x10 I'm unsure; It has 3 plastic removable separators that slide into slots, how many do I want in if I am doing a sheet of 8x10?

    3.) How much chemistry should I use?
     
  2. Konical

    Konical Subscriber

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    Good Evening, Ben,

    I just pick up the drum at regular intervals and reverse it on the motor base. I suspect that, for most film/developer combinations, it probably matters very little or not at all whether manual reversal is done. For times in the 10 minute range or longer, I'll do the first couple of reversals at 30-second intervals, then just once a minute after that. (I do use pre-soak.) Manual reversal a good way to reduce the boredom even if it's not really necessary.

    I occasionally make a contact sheet (8 x 10 or 8 1/2 x 11) in the drum rather than preparing full trays of chemicals. For 8 x 10, I use the two separators at the "bottom" positions and omit the third one. For 8 1/2 x 11 paper, I don't use any of the separators. The same approach should be fine for film.

    Since the only film I do in the drum is 4 x 5 B & W, the cost of chemicals is fairly insignificant, so I don't try to get by with the smallest amount possible. For most film, I'll use at least 10 or 12 oz. of developer. For the other chemicals, I use at least that much, but I'm only concerned about not using so much that some spills out during the rotation.

    Konical
     
    Last edited by a moderator: Oct 13, 2009
  3. BenZucker

    BenZucker Member

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    sorry to bring up an old thread here, any how I know I am going to have to test, but to get into the ball park of the right dev times.....should I just start with the tray time? less or more time than that? any advice on a starting point? Im going to be using trix 320 and HP5 in rodinal (any recomendations on dilution?) or in hc110 Dilution B.
     
  4. Mike Wilde

    Mike Wilde Member

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    The thumbnail estimate for adapting to continuous agitation from intermittent is usually less 15%. Use it as at least as a starting point on your way in you refinement effoits.
     
  5. Greg Davis

    Greg Davis Member

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    If you look up the spec sheets, development times for rotary drum processing are usually included. I know Kodak includes them. You can extrapolate the times for rodinal from that.
     
  6. Konical

    Konical Subscriber

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    Good Afternoon, Ben,

    Starting with the film manufacturer's specified time for continuous agitation is a good starting point.

    Konical