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  1. #1

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    Kodak Flexicolor C-41 Chems in a Jobo

    I've been looking into getting some Kodak C-41 chemistry for developing 120 and sheet film in my Jobo and am wondering whether the capacity of the Kodak stuff will be a problem. Other C-41 developers I've used (Agfa, Tetenal) have a capacity of 10-12 rolls of film per liter, but Kodak recommends only developing 3 rolls of 120 per liter (Kodak document z131_03, page 3-5). This means I'd have to put a whopping 2 liters of dev in my Multitank with 6 rolls. With this much in the tank, the liquid level is above the inlet, which could work but would probably leak a bit. It also means that the Kodak chemistry is not so economical. For the 1 gallon size, anyway, the cost per roll is about what I can have it done for at my local pro lab. With sheet film it's more attractive because the lab charges more per unit area for that type of film.

    Does anyone know why Kodak's developer capacity is so low compared to that of other manufacturers'? Is it because Kodak chemicals optimised for replenishment in commercial systems?

    Jim

  2. #2

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    You use the chemicals in the Jobo as a one-shot. I use 300cc per (small) tank, giving me three tanks per liter. Use about the amount of chemicals Jobo recommends, maybe a bit more if it's convenient. I haven't tried the Multitank, but 300cc works well with 2 rolls of 120 or one roll 0f 220 or 6 sheets of 4X5 in the smaller tank. I think the Kodak caution may have to do, at least in part, to the effects of partial exhaustion when using the same chemicals for multiple tanks and developing sessions without replenishment. Partially exhausted chemicals can be unpredictable.

  3. #3

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    Hmm... the capacities I quoted were listed as being for unreplenished development (i.e. one shot), so it's interesting that you're able to get away with using half of what Kodak recommends... maybe they're being a little conservative, but by a factor of 2?

  4. #4

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    That would not surprise me at all. Kodak's reputation, at least as far as the materials I work with, is to provide extremely conservative recommendations regarding chemistry capacity and longevity. The same can be said for film expiration dates.

  5. #5

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    The values Kodak are recommending sound more for an inversion tank. My paterson uses 500ml for two films where as the Jobo will use 230ml.

  6. #6

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    Quote Originally Posted by LAMitchell
    The values Kodak are recommending sound more for an inversion tank. My paterson uses 500ml for two films where as the Jobo will use 230ml.
    I don't think that's it - the values that the tank manufacturer specifies is how much liquid you need to fully cover the film - whether this volume of developer has the capacity to develop the film in the tank is something totally independent. The chapter of the document that the figures came from is titled "Sink Line, Batch and Rotary Tube Processors"

  7. #7

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    Quote Originally Posted by j_landecker
    Hmm... the capacities I quoted were listed as being for unreplenished development (i.e. one shot), so it's interesting that you're able to get away with using half of what Kodak recommends... maybe they're being a little conservative, but by a factor of 2?
    I looked up your reference on the Kodak website. It only adds to the confusion. The capacity figures are only given for the sink line process (unreplenished). Under the tube processing section, Kodak makes a point of "follow the manufacturer's instructions." It also remarks on how tube processors can give satisfactory results using only a small volume of chemicals. The instructions specifically refer the user to Section 1 of the document to identify the chemicals to use, but they appear to be the same ones used in the sink line process. It seems to be a uncharacteristicly sloppy document from Kodak. In any case, following the Jobo instructions for tank fills seems to work, and adding a bit more (about 10 percent in my case) doesn't hurt.



 

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