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  1. #1
    GRHazelton's Avatar
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    Storage life of unmixed C41, E6 developing kits?

    Considering the rapid disappearance of color films both slide and negative and contemplating the sizeable store of such in my freezer, I wonder if I should stockpile E 6 and C 41 processing kits. Does anyone have any thoughts about the shelf life of unmixed, factory sealed kits? Would refrigeration, NOT FREEZING, extend their shelf life? Its ironic. When I am finally able to afford used the gear I once only could dream of, the film to use in them becomes scarce. I would hate for my Pentax 645n kit, my LX's, my Retina IIIc, my Vitessa L to languish for lack of "fuel."

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    David Lyga's Avatar
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    Again: keep in either glass or clear plastic bottles (soda, juice, water, etc) FILLED TO THE RIM. Use glass marbles to take up the slack. I am talking 'indefinitely' as to the time you can keep them. In other words: forever. Period. When I am buried you may have my remaining C-41 dev and RA-4 dev. Few believe this solution for preservation. - David Lyga

  3. #3
    GRHazelton's Avatar
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    Quote Originally Posted by David Lyga View Post
    Again: keep in either glass or clear plastic bottles (soda, juice, water, etc) FILLED TO THE RIM. Use glass marbles to take up the slack. I am talking 'indefinitely' as to the time you can keep them. In other words: forever. Period. When I am buried you may have my remaining C-41 dev and RA-4 dev. Few believe this solution for preservation. - David Lyga
    Many thanks for the quick response. It sounds as though you are describing ways to store already mixed and perhaps already used solutions. Good to know! I've also heard it suggested that displacing the air above the solutions with something without oxygen, propane, butane, canned "air" is efficacious. I would guess that the choice of plastic bottles might be significant, since I've read that some plastics allow diffusion of gases through the plastic.

    Any thoughts on refrigeration?

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    heterolysis's Avatar
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    The colder it's kept, the longer the shelf life, theoretically.


    Are you talking about powders or liquids?

    Liquids will benefit greatly from being kept cold. Powders it won't make much of a difference. Liquids in a fridge will be roughly 20C below room temperature and should theoretically last 2^2= 4 times as long as their listed shelf life, if they have one. And this is probably a gross underestimate of it, since they live longer than shelf life to begin with.

    Vacuum sealed powders will probably last forever.

  5. #5
    GRHazelton's Avatar
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    Quote Originally Posted by heterolysis View Post
    The colder it's kept, the longer the shelf life, theoretically.


    Are you talking about powders or liquids?

    Liquids will benefit greatly from being kept cold. Powders it won't make much of a difference. Liquids in a fridge will be roughly 20C below room temperature and should theoretically last 2^2= 4 times as long as their listed shelf life, if they have one. And this is probably a gross underestimate of it, since they live longer than shelf life to begin with.

    Vacuum sealed powders will probably last forever.
    Liquids. I seem to recall from college chem courses that chemical activity roughly doubles with each 10 C rise in temperature. This would suggest that each comparable drop in temp would halve deterioration, although enough drop might precipitate components which might then be difficult to redisolve. So, with the proper temperature for a fridge being perhaps 35 F what will precipitate out, and can it be re-dissolved? Any experience out there? I know that some formulae for developers specify the temperature of the solute and the order of addition of components; this suggests that cooling below STP might be deleterious.... Any photo chemists out there who might weigh in?

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    polyglot's Avatar
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    Do not open them! They are packed under nitrogen in the factory and far better sealed and protected from oxygen than you can manage at home. Glass, marbles, butane and all that bullshit is useful only once you have opened containers.

    Refrigeration certainly helps on the mixed up solutions, but they do have oxygen available to them in the solution water. It may or may not help with concentrates depending on how well they're packed and if they're using water or TEA as the solvent, i.e. on the availability of things that the active ingredients can react with. If you're going to refrigerate, only bother with the developer parts (and maybe E-6 reversal+pre-bleach) because the bleach, fix, etc won't really go off. Handily, those parts are physically much smaller.

    Powders will last the longest of course. Up to you whether the processing quality of powder kits is sufficient, as they tend to be blix kits.

    The other thing is that the chemistry is all available as component chemicals. I've never DIY'd it myself but there are people here who have and I wouldn't expect it to be particularly difficult as long as you can physically buy the right chemicals.

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    Yesterday I developed a roll of expired (7/11) Ektar 100 film that I shot over the weekend. The film was kept refrigerated in the wine cooler so I wasn't too concerned about the film; but I was as bout the Kodak C-41 developer kit which I originally opened on 1/1/2011 - two and a half years ago! I went on the Kodak web site to consult the Tech Pub that tells you how to determine the condition of the chemistry by their coloration. The colors indicated that the chemistry was good and the roll turned out fine although I haven't printed the negatives yet. This was the Kodak 5 gallon kit and the bottles have "0833" stamped on them which may mean that they were mfg during the 33d week of 2008. I was also concerned about the C-41 fix which I first opened on 5/10/2009 and the date stamped on it is "0814."

    Thomas

    PS: The chemistry above was not kept refrigerated nor was there any attempt to shield the contents from oxygen other than keeping them tightly caped.
    Thomas

    No art passes our conscience in the way that film does, and goes directly to our feelings, deep down into the dark rooms of our souls.
    — Ingmar Bergman

  8. #8
    AgX
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    Quote Originally Posted by polyglot View Post
    Do not open them! They are packed under nitrogen in the factory and far better sealed and protected from oxygen than you can manage at home. Glass, marbles, butane and all that bullshit is useful only once you have opened containers..
    A glass container would be diffusion-tight in contrast to an original plastic container.
    It is possible (though a hassle) to refill chemistry from one container to another without losing a nitrogen topping.

  9. #9
    polyglot's Avatar
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    Quote Originally Posted by AgX View Post
    A glass container would be diffusion-tight in contrast to an original plastic container.
    It is possible (though a hassle) to refill chemistry from one container to another without losing a nitrogen topping.
    The original plastic containers (at least, the ones I've received from Fuji) are HDPE, which is quite impermeable. The oxygen dissolved in the water that the concentrates are made up in is far greater than the oxygen that can diffuse through the container.

    Anything that someone does at home is going to ruin the nitrogen filling and run far greater risks than just leaving the chemicals in the manufacturer's containers.

    Once you've opened the containers of course, by all means transfer stuff to glass bottles etc. The concentrate containers often don't seem to seal very well once the thermal seal is broken.

  10. #10
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    I don't think anyone really needs to worry about whether the plastic is permeable to oxygen or not...

    But if you feel like transferring to glass bottles, sparge the solutions thoroughly with an inert gas afterwards. Fill a balloon with nitrogen or another inert gas, then tape the opening over a small rubber tube. Bubble the gas through the solutions and they'll be fine afterwards.

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