How well do floating lids work

Discussion in 'B&W: Film, Paper, Chemistry' started by Mainecoonmaniac, Mar 11, 2013.

  1. Mainecoonmaniac

    Mainecoonmaniac Subscriber

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    I'm curious about how well do floating lids work on film processing tanks? Can one store developer indefinitely in a 4x5 film tank without oxidation with floating lids? I know that stop and fix effected too much by air. Am I correct?
     
  2. BMbikerider

    BMbikerider Member

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    The lids on my NOVA Processors do very much the same thing but I follow a strict procedure when I have finished printing to make sure they are optimised.

    I top up/replenish the developer, stop bath, and blix when I have finished, wipe the edges of the tank dry and then with the floating lids in place, cover the whole of the top of the tank with cling film to make it as airtight as possible. When the solutions cool down, if I have obtained a good seal, the cling film allows a semi-vacuum to form in the tank. (I only worry about the developer) You can tell this has happened when the surface of the cling film which was previously flat, takes on a concave depression.

    I have done this for as long as I have been processing colour and the RA4 developer (Kodak Ektacolour) has lasted as long as 18 months so long as it replenished properly. I only need to change it when the build up of tar gets too much.

    So yes, in the right circumstances they do work.
     
  3. georgegrosu

    georgegrosu Member

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  4. George Collier

    George Collier Member

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    We used them in the Army with a replenishment scheme. Used once a day for a month or two with DK50 in 8x10 tanks. Now, my standards might be higher today, but it worked and contrast was consistent, or we'd have known it when printing.
     
  5. Prof_Pixel

    Prof_Pixel Member

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    I think 'indefinitely' is the problem word. Nothing last forever. I used to use them on 4x5 tanks and though they worked much better than repeatedly pouring the developer from a bottle to a tank and then back to the bottle (and so forth).
     
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  6. Mainecoonmaniac

    Mainecoonmaniac Subscriber

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    Thanks for the great info. I guess all this pouring between tank and bottle causes oxidation.
     
  7. laser

    laser Advertiser Advertiser

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    If you want one I listed an 8x10 floating lid in the APUG Classified section.


    It will not provide infinite developer life but preventing exposure to the air is the best way increase developer life. This is a tried and proven easy way to increase developer life
     
  8. Mainecoonmaniac

    Mainecoonmaniac Subscriber

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    Thanks! But I don't have an 8x10 tank :sad:

    It looks like it's in good shape.
     
  9. presspass

    presspass Member

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    I have used floating lids on 4x5 tanks with X-tol developer replenished and had it last 18 months. It might have gone longer, but I got nervous. There was considerable buildup of caked/dry fixer around the lid of that tank, though.