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  1. #31

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    Quote Originally Posted by Buggs View Post
    Gerald,

    Do you think in the case of a print developer where a significant quantity is removed with each print, bromide build up would be minimized?

    thanX,
    tim
    There are two problems with print developers other than bromide buildup. Their higher pH relative to film developers makes them more prone to oxidation and their constant exposure to air while in a tray compounds the problem. The result is much higher oxidation than for a film developer. The buildup of oxidation byproducts can cause print staining. I personally would never replenish an MQ print developer for this reason. A PQ print developer like LPD presents a somewhat more favorable situation.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

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  2. #32
    MattKing's Avatar
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    Quote Originally Posted by presspass View Post
    As far as I know, Xtol is the only developer that also serves as its own replenisher.
    T-Max RS also serves as its own replenisher.
    Matt

    “Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”

    Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2

  3. #33

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    Quote Originally Posted by Gerald C Koch View Post
    A major bugaboo with MQ developers and their replenishment is bromide buildup. This effectively limits the number of times a system can be replenished unless a large volume of the developer (say 1/3 of the volume) is dumped periodically in order to bring the bromide level down.
    Quote Originally Posted by Buggs View Post
    Gerald,

    Do you think in the case of a print developer where a significant quantity is removed with each print, bromide build up would be minimized?

    thanX,
    tim
    I think it needs to be pointed out that bromide CONCENTRATION is the important thing in a developing solution. And concentration can never by reduced by dumping part of the solution nor by the carry-out due to wet film or paper. Solution volume is reduced, but not concentration.

    I'm not a chemist, my knowledge is more on the level of a tech or Chem E, but I have quite a lot of experience in replenished systems. Mainly in color neg/print going back to C-22, but a few low volume B&W machine lines such as Kodak Selectomat and Versamat developers. It is never my experience that a well-designed and operated replenished system needs to be periodically dumped. To be clear, my experience is mostly in machine processing, on a scale probably beyond the imagination of most members here.

    I've never tried to replenish a tray system, though, so anything I could say about that would only be a semi-educated guess. This may not be obvious to everyone, but a tray has a large surface area compared to its volume. By comparison, a processing machine might be 3 or 4 or 5 feet deep, so the surface-area to volume ratio is improved on the order of about 100 times. So one expects the tray system to be worse on both oxidation and evaporation by roughly the same factor.
    Last edited by Mr Bill; 12-17-2013 at 01:21 PM. Click to view previous post history.

  4. #34

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    Quote Originally Posted by Mr Bill View Post
    I think it needs to be pointed out that bromide CONCENTRATION is the important thing in a developing solution. And concentration can never by reduced by dumping part of the solution nor by the carry-out due to wet film or paper. Solution volume is reduced, but not concentration.
    Bromide concentration is reduced when the volume is increased by the addition of replenisher which usually contains no bromide. If the amount of replenisjer per roll is small then it is important to periodically dump a large portion of the developer to bring the bromide concentration back to a satisfactory value.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  5. #35

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    Gerald, you're not describing a proper replenished system. It sounds like some sort of variable system where the bromide level never stabilizes.

    In a proper system, the bromide concentration should be stable, at a level defined by the formulator. If you were to process some unit of film, such as a roll, the specified volume of replenisher should be just right to maintain the bromide concentration. It shouldn't matter whether the tank volume is 1 gallon or 100 gallons, the film/replenisher relationships stay the same.

    I've spent a fair amount of my life setting up and troubleshooting regenerated and replenished systems, so I'm not just speaking hypothetically. If you find that the bulk of your developer is running at a different concentration than your current input, then it's either not a proper replenished system or you have some sort of process problem going on.

  6. #36

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    What is the negative effect of having a high concentration of bromide in a developer, paper developer in particular.

    thanX,
    tim

  7. #37
    Thomas Bertilsson's Avatar
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    Quote Originally Posted by Buggs View Post
    What is the negative effect of having a high concentration of bromide in a developer, paper developer in particular.

    thanX,
    tim
    It acts as a restrainer, so it holds back development. In some cases, and in limited quantity, this can be a much desired quality!
    But too much of it, and you start to negate the effect the developer should be having, i.e. developing the film.
    "Often moments come looking for us". - Robert Frank

    "Make good art!" - Neil Gaiman

    "...the heart and mind are the true lens of the camera". - Yousuf Karsh

  8. #38

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    Quote Originally Posted by presspass View Post
    As far as I know, Xtol is the only developer that also serves as its own replenisher.
    sprint film developer works as its own replenisher too
    ask me how ..

  9. #39

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    thanX Thomas, that's exactly what I thought.

    I'm thinking more about ansco 130 where I can directly observe the results of bromide build up. Shortly I'll be mixing up a fresh batch and plan on comparing prints with fresh and used developer. Then I should be able to make an informed decision about topping off my bottle of used dev.

    tim

  10. #40

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    Quote Originally Posted by Buggs View Post
    thanX Thomas, that's exactly what I thought.

    I'm thinking more about ansco 130 where I can directly observe the results of bromide build up. Shortly I'll be mixing up a fresh batch and plan on comparing prints with fresh and used developer. Then I should be able to make an informed decision about topping off my bottle of used dev.

    tim
    130 works great for film too, great developer to work with.
    ask me how ..

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