Powder fixers - Can they be mixed up in small batches?

Discussion in 'B&W: Film, Paper, Chemistry' started by SteveR, Jul 28, 2012.

  1. SteveR

    SteveR Member

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    Hi all,

    Just a quick query, other than Hypam many years ago, I've always used Ilford Rapid Fixer. With a young family my printing (& film developing) is very sporadic, going through phases of great productivity, then a massive dry spell where I still shoot, but don't have the chance to get any wet-work done. The thought just crossed my mind the other day when I opened a new bottle of fixer, I realised I'd gone through a bit recently, and thought "Gee, it would have been more economical if I had gotten a 5L bottle last time...", that was very quickly followed by "Hmmm... we've got a lot coming up over the next couple months, I don't know when I'll next be using this bottle...?". I store my stock fixer in concertina bottles of course, but still, it got me thinking about other options.

    Of the powder fixers commercially available, is it practical for any of them to be mixed up in smaller (enough for a few uses) batches, or do they need to be made up in one big batch? I'm assuming, after opening, their storage life in powder form would be pretty long if they were kept in air-tight storage, am I right? Or would I be better looking at a diy fixer that I can mix up in batches to suit my needs?

    Thanks for the input, really appreciate it.
     
  2. Steve Smith

    Steve Smith Subscriber

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    The usual advice is no as you can't guarantee that you have an equal mix of ingredients in the divided parts. However, if you think you can mix the powder sufficiently to evenly distribute the ingredients then it should work.

    Probably less critical with fixer than with developer.


    Steve.
     
  3. SMBooth

    SMBooth Member

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    Steve. why not just buy the chemicals for a plain fixer and mix as you need.
     
  4. tkamiya

    tkamiya Member

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    I thought about this earlier in my film processing habbit.

    When I used powder type (I now use Ilford rapid which is liquid), I always mixed the whole bag. It'll give me a gallon. I use it for 6 months or exhausted by number, then replace it. Sometimes it's wasteful but a bag costs something like 6 dollars and I can have it ready for 6 months. It's the smallest part of the entire expense.

    Paper costs much more. Gears cost much MUCH more.

    Now that I use liquid, I mix a gallon worth and divide it into 1/2 gallon bottles for fix1 and fix2. Then the remaining concentrate is used 6 months later.

    I don't worry too much about economy of chemicals anymore as in absolute terms, they are the smallest part of my expense.

    If you want to mix-for-use type thing, you might want to use liquid. Making partial bag is an often discussed topic on apug and there's no solid answer. It's always a "mixed bag". If you shake it well and use half of it, it should be reasonably close. Yet, I don't practice this method.
     
  5. Leigh B

    Leigh B Member

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    Sorry to disagree, but it's impossible to uniformly distribute any multi-element compound by physical means.
    The result is dependent on many factors, including grain size and density.
    All instructions for developers and such that address the question at all say not to mix partial quantities.

    As someone else suggested, if you really want small quantities, buy the constituent chemicals and mix from scratch.

    Close only counts in horseshoes and hand grenades. :D

    - Leigh
     
  6. Bob Carnie

    Bob Carnie Subscriber

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    I agree with this... Chemicals are your least expensive area of printing why take any chances.
     
  7. john_s

    john_s Member

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    Even if some of the ingredients are not fully dispersed amongst the different batches it can hardly make a difference. I wouldn't hesitate to mix up small batches of powdered fixer.

    It's not like developer where, for example, tiny amounts of phenidone or bromide could be unequally dispersed, making different batches behave differently.
     
  8. wildbill

    wildbill Member

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    I guess as long as you have a good return policy on the prints you're selling/giving away, then it's okay to use fixer that may or may not do the job from batch to batch.
     
  9. walbergb

    walbergb Subscriber

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    Mix the whole package and store in smaller containers that suit your needs.
     
  10. markbarendt

    markbarendt Subscriber

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    I'm in the mix-up-the-whole-batch camp.

    Firstly fixers keep really well. The only stories I've heard about fixer death are from use, not storage.

    Second, as Bob pointed out, chemicals are pretty darn cheap compared to the rest of our photographic expenses.
     
  11. bdial

    bdial Subscriber

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    The powdered fix may well be all sodium thiosulfate, in which case, you can mix small batches at will. But fix keeps much better than developers, the stock solution should last 1 - 2 years.
    FWIW, I and many others have found that the "concertina" bottles tend to leak air, glass or PETE plastic are better.
     
  12. markbarendt

    markbarendt Subscriber

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    Recycled wine "boxes" are great for storage too.
     
  13. SteveR

    SteveR Member

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    Thanks for all the input guys, appreciate it. I've not been so worried about the cost of wasting chem, since as you say, it's cheap, and particularly fixer. It's more just that I'm tight (good Scottish upbringing!) and don't like to waste anything.

    I had wondered about the concertina bottles leaking, at the moment I only use them for my dilute Selenium and working solutions of fixer and paper dev, which might last a few sessions. And a small one for fixer concentrate too. My stock developers both live in large bladders, and store really well.. Maybe I'll have to get another one to pop fixer in and just start getting the 5L bottles.

    Thanks again for the comments.
     
  14. tkamiya

    tkamiya Member

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    I'm not sure if you realize fixers are re-usable until exhausted. They don't really deteriorate by exposure to oxygen like developers and HCA would. I use mine until specified number of films/papers are processed or 6 months. Unless you are doing HUGE volume, it will certainly last longer than few printing sessions.

    Also, selenium working solution lasts and lasts. I think I used my 1:40 solution for a year. At which point, the ammonia smell was weak and action was equally weak, so I replaced it.
     
  15. Gerald C Koch

    Gerald C Koch Member

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    This type of bottle is the worst possible choice for two reasons. The soft polyethylene that they are made of is very permeable to oxygen and not good for developers. Because of their design they are impossible to clean should anything get on the inner surface. Soft drink bottles made of PET plastic are a good choice and are virtually free.
     
  16. Stan160

    Stan160 Member

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    I've got a 5L bottle of Agfa fixer that's been open for over 2 years so far, and probably still about a litre left. I didn't bother decanting the concentrate into smaller bottles or using Protectan. I'd guess the date of manufacture to be at least 5 years ago, because I bought the bottle for 17p when Jessops were having a clearout!

    Still works the same as when first opened, and yes I do test the occasional print with selenium toner, and film clearing time just to be sure.

    Ian
     
  17. SteveR

    SteveR Member

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    Thanks again for that input guys. Yes, my working fixer hangs around for a few sessions or more, I usually end up just splashing a little extra stock in I feel it's getting a bit tired, then replace it after that session. I had a great collection of these concertina bottles a number of years ago, in the darkroom I learnt in nearly 20 years ago they were all we had, but then I found out about their shortcomings! That's why now I only use them for working solutions that are only going to be in them for a couple weeks, and my dilute selenium, figuring it should last well no matter where I put it. My current batch has been in a concertina bottle and going strong for over two years, with jut a little top-up when times get too far over the 3 minute mark.

    Good to hear of stock fixers lasting a while, I had always assumed (I think the Ilford data may state?) that 6 months was the limit for opened bottles, and one week the limit for working solution... Or maybe I have just always err'd on the cautious side.