washing negatives - Does the fixer leach out?

Discussion in 'B&W: Film, Paper, Chemistry' started by Harry Lime, Apr 12, 2007.

  1. Harry Lime

    Harry Lime Member

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    Hello everyone -

    When you wash negatives is the removal of fixer etc. more of a leaching process, than an actual washing process due to the constant flow of water over it's surface?

    If you were in a location where you did not have access to a lot of running water, could you 'wash' a negative by changing the water in the tank every few minutes via a slow flow from the tap, rather than the usual high flow with bubbles etc? I'm guessing you would have to bump the wash time somewhat.


    Thanks,

    HL
     
    Last edited by a moderator: Apr 12, 2007
  2. Leon

    Leon Member

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    ILFORD recommend this for film - take a look at their film development PDF on the ilfordphoto.com website.

    Typically, I fill the tank with water, invert 5 times, dump. Then same for 10 inversions, 20 inversions, 30 inversions and finally another 20. then one fill of distilled water with a little ilfotol in it and job done. I understand the thinking is that a small amount of reisdual fixer is actually beneficial for longevitiy and this method seems to leave the desired amount.
     
  3. Roger Hicks

    Roger Hicks Member

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    It's a simple diffusion process, the rate of which depends on the concentration gradient, so yes, leaching is an entirely fair description.

    Ilford's recommendation when using a non-hardening fixer is 5 - 10 - 20 inversions (fresh water each time). You do not need to wait 5 minutes between changes or anything else, regardless of advice elsewhere to the contrary.

    Almost no-one believes that this will work (despite the fact that you can test it by any means you like) so everyone gives more.

    I generally do 5 - 10 - 20 inversions with tap water (super hard where I live), then dump and refill with distilled water and leave it in there until I transfer it to the final distilled water/wetting agent rinse for 30-90 seconds.

    With hardening fixer -- inexplicably popular in the United States and Japan, little used elsewhere -- you're on your own.

    Cheers,

    r.
     
  4. DJGainer

    DJGainer Member

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    I actually just let my negatives soak in 3 changes of water. I am never in any rush when developing, so I use the time to clean up my work area. Instead of doing 5-10-20 inversions, I do 10-10-10 minutes.
     
  5. gainer

    gainer Subscriber

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    You clean up your work area? Are you sure your name is Gainer?
     
  6. jim appleyard

    jim appleyard Member

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    I smell a sibling plot here!:D
     
  7. Roger Hicks

    Roger Hicks Member

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    A little agitation is not a bad idea. I am sure you are aware of this, but others may not know that the old ideas about 'heavy, hypo-laden water' are simply not true. Because it's a simple diffusion process, bringing cleaner water into contact with the film is a very good idea indeed.

    Also, most manufacturers recommend minimum wet time, and the 5-10-20 inversions allows the process to be over in 5 minutes or less, not half an hour, during which time the gelatine swells still further and becomes even more tender.

    Cheers,

    R.
     
  8. Dave Miller

    Dave Miller Member

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    Roger, you missed the bit about the fill and dump method being good exercise.
     
  9. DJGainer

    DJGainer Member

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    I agree with what you are saying, but fear that 35 inversions do not provide enough time for the fixer to diffuse from the emulsion. As for the swelling, I figure that I use TF4, which keeps my fixing times short, and if I were to use a hardening fix, without hypo clear, I would need to fix for a longer period anyhow. If I ever notice damage to the emulsion, I'll dig up this thread and post about it.
     
  10. Thomas Bertilsson

    Thomas Bertilsson Subscriber

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    For how long has Ilford published their 5-10-20 method? I'm curious to see what the success rate has been.

    Oh, and Dave, imagine how much exercise Leon is getting, doing 5-10-20-30-20! Lean, mean film developing machine!

    - Thomas
     
  11. Roger Hicks

    Roger Hicks Member

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    Well, as I said, we all fear that, which is why we all wash for longer, including me. But amazingly, no test I have yet seen has found that the film is not fixed to ANSI archival standards, even with that astonishingly short immersion. I'm not familiar with TF4 but use a conventional film-strength fixer (Ilford) and have tested the film (not for years) and found that it works. And like you, I still don't fully believe it...

    Cheers,

    R.
     
  12. Thomas Bertilsson

    Thomas Bertilsson Subscriber

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    I believe it because it's convenient... :smile: Saves water and time. Even if your negatives last 100 years instead of 110, at least we saved some water and time...

    - Thomas
     
  13. dancqu

    dancqu Member

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    [QUOTES=Roger Hicks;454416]
    "It's a simple diffusion process, the rate of which
    depends on the concentration gradient, so yes,
    leaching is an entirely fair description."

    A diffusion process predominately and most so after
    the first cycle. Diffusion is the movement of molecules
    from an area of higher concentration to an area of lower
    concentration; fixer moves into the water and water
    moves into the emulsion.

    "Ilford's recommendation when using a non-hardening fixer
    is 5 - 10 - 20 inversions (fresh water each time). You do not
    need to wait 5 minutes between changes or anything else,
    regardless of advice elsewhere to the contrary."

    Like one or two others posting to this thread I use a relaxed
    Ilford sequence. I've clean up to do as well. In with the water,
    a few inversions, sit a while, a few more inversions then out and
    in with fresh water. I allow for all the inversions but consider the
    sit and diffuse time important and a better use of the water.
    Start to finish, about ten minutes. Distilled water 1/2 liter
    per change, room temperature.

    "I generally do 5 - 10 - 20 inversions with tap water (super hard
    where I live), then dump and refill with distilled water ..."

    Super hard tap water. Impurities. I've hard water and
    avoid insoluble silver thiosulfate complex formation by
    the use of distilled water from the very start. I know,
    pure water is not recommended for washing as it
    takes some more time. Dan
     
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  15. dslater

    dslater Member

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    I had never heard that - why would pure water take longer to wash?
     
  16. dancqu

    dancqu Member

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    It has to do with the hca property of water contaminated
    with types of chemistry which if present speed washing.

    My precaution deals with films and papers taken from a
    fixer laden with silver thiosulfate complexes and then set
    in impure water. The sodium and ammonium complexes are
    soluble but some water impurities may form very insoluble
    complexes. They may precipitate in or on emulsions
    and dirty the fixer. Dan
     
  17. Maine-iac

    Maine-iac Member

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    I had very hard water in Paris, combined with little particulates of calcium that were visible. I solved the problem without resorting to buying distilled water. I just used water-softening crystals of the sort that were sold in every grocery store for dishwashers. I think they were just a larger granulated form of Calgon. About a teaspoon per liter did the trick plus 3-4 drops of Photo-Flo. In my case, I would do either a 1-minute running water wash or several fill-and-dumps using the regular tap water. Then for the final fill, I would use the liter of "softened" water with the Photo-Flo that I had mixed up (it could be re-used for many rolls before needing to be replaced). This left my negs streak free and thoroughly washed.

    Larry
     
  18. dslater

    dslater Member

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    Umm - what does hca stand for?
     
  19. Roger Hicks

    Roger Hicks Member

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    Dear Dan,

    Yes, of course, there is initial plain washing-off, not diffusion -- and as K.C.D. Hickman pointed out, you're washing the tank at least as much as the film. But this happens anyway with any wash. After the first wash, as we agree, it's a simple diffusion process depending on the diffusion gradient, but I'd dispute your assertion that 'pure water diffuses in' which is a bit like saying 'letting the cold in' rather than 'letting the heat out'. Yes, water taken up by the gelatine, but this is nothing to do with the diffusion required for washing, which is getting the fixer (and fixer products) out.

    Letting it sit won't do any harm, provided it's not absurdly long, but it's not actually needed; I was referring to the Anchell and Troop exhortation that you should always let the tank sit for 5 minutes at each stage: no-one else I know, who is familiar with this washing technique and has tested it properly, agrees. And, of course, minimum wet time = minimum fragility and swelling + minimum drying time. C.E. Ives suggested that spray washing can reduce wash times by a factor of 50 as compared with low-agitation immersion methods.

    As for 'super hard tap water. Impurities', I'd be interested to know what 'insoluble silver thiosulphate complexes' you have in mind. After all, wash-aid is impure water, and to quote Haist p. 671) '...pure water makes a poor washing medium. Hard water with dissolved salts, especially bicarbonates, or soft water with sodium bicarbonate present at a fraction of a gram per liter, is superior to pure water in washing power...' Similar observations are made by every other authority; I have never seen any references to 'insoluble silver thiosulphate complexes' as a result of washing in hard water. If you can provide references, I'd be intrigued.

    Cheers,

    R.
     
  20. GeorgesGiralt

    GeorgesGiralt Member

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    Hi All,
    In response to Thomas asking for how long Ilford gave this advice, I must say that I learned B&W process in the early seventies and this was the way I was told to wash film.
    Last but not least, a German guy (I think he is German) had done a nice test job on washing. He confirms the Ilford washing procedure. You'll find the results here :
    http://www.geocities.com/ResearchTriangle/Thinktank/5693/photogra.html
    Last but not least, I had a print course given by a renowned French printer running a comercial printing lab in Paris. In order to be sure to deliver archival prints to his customers, he had it's process checked by scientists and improved by them to reduce water consumption (water is metered in France and paid at a premium price now because production has gone from public to private).
    He does print washing by transfering prints sgeeged from an emptied tray to a full tray of fresh water repeat the process after the emptied tray is full of fresh water for an half an hour. He let the less skilled assistant process them ......
     
  21. Ryuji

    Ryuji Member

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    Not quite. The first few moments of washing can be approximated by simple diffusion process but not the later half of the washing period. Washing of fixer is actually a two-stage process. The first is desorption and the second, diffusion. So, the time-concentration function is actually a doubly exponential function with two time constants associated with it.

    The reason why first few moments can be approximated by a simple diffusion process is because it is still governed by the diffusion process of smaller time constant. Or you can think of there are many non-adsorbed thiosulfate and silver-thiosulfafe complex ions that do not require the desorption process to come out.

    I believe it works but I give much more time for the last wash (tho not agitating for the entire duration) is to remove sensitizing dye.
     
  22. Ryuji

    Ryuji Member

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    Who told you that? The kind of silver-thiosulfate complex that are difficult to come out are actually very sparingly soluble in water and you are SOL even if you used pure water for that matter. To prevent this, (1) don't let fixer exhaust (2) use two-stage fixation if you need to be iron clad fail-safe (3) use sulfite based washing aid. Washing aid is very helpful in your situation.
     
  23. Ryuji

    Ryuji Member

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    Refer to my earlier post for that washing is not a simple diffusion process.

    Also, not that this makes a significant difference with modern films, extra swelling of gelatin can affect the diffusion process because the diffusion path will be longer with swollen gelatin.

    Well, is this the only thing in Anchell and Troop that no one else agrees?

    I don't mean to intrigue you unnecessarily but if you wash fixed film in strong KBr solution there will be some insoluble silver thiosulfate salt, often called "B-salt" in photographic chemistry.
     
  24. Roger Hicks

    Roger Hicks Member

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    First point taken; simple ignorance on my part.

    Second point: that would be pretty weird hard water.

    Cheers,

    R.
     
  25. Ryuji

    Ryuji Member

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    Yup, we both think Dan has weird water if his theory is true.
     
  26. dancqu

    dancqu Member

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    Been busy. What does hca stand for? It stands for
    hypo clearing agent; also known as wash aid. KHCA
    is Kodak's version. There are many. Of the many on
    the market by far the majority, perhaps all, are based
    on one or two sulfites; sodium and or ammonium.

    I think all are of the one-size-fits-all design. I've not
    read of any hca that wouldn't do for film or paper, acid
    or alkaline wash water. For the most part the use of a
    wash aid is confined to fiber base papers for which it
    is much recommended. It's use follows fixing and a
    rinse may or may not immediately precede. Dan