Alkaline vs. Acid fixers

Discussion in 'B&W: Film, Paper, Chemistry' started by Thomas Bertilsson, Aug 19, 2004.

  1. Thomas Bertilsson

    Thomas Bertilsson Subscriber

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    Hi,

    this has probably been covered here before, but since I can't seem to find the threads, I ask:

    What is the advantage of an alkaline fixer, as opposed to an acid one?

    A film like Efke, with an old style emulsion, i.e. not pre-hardened, would surely need a hardening, acid fixer, wouldn't it? Or is that just manufacturer "market training" talking?

    I do know that alkaline fixers usually washes out quicker than acid fixers, unless you're making prints and using fixer at film strength - it is supported by research by Ilford that it provides sufficient fixing with radically shortened times for both fixing and washing using this technique.

    I would be delighted to hear the pros and cons of either fixer.

    Much obliged,

    - Thomas
    Saint Paul, Minnesota
     
  2. galyons

    galyons Member

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    Thomas,
    There are a lot of variables to consider here. As an example, how are you processing? What developer? I use Jobo drums with Efke 25/50/100. I also use ABC Rollo Pyro, which is a staining, tanning developer. Acid fixers cut the stain. I don't need the hardener due to the tanning effect from the pyro. I prefer to keep acid out of my process for both film and prints. One using different processing/developer combinations may want to use other fixers.

    Geary
     
  3. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member

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    The main reason to use an alkaline fixer is to prevent reduction in stain with a staining developer like pyro. Other attractions are that it eliminates the need for an acid stop (acid stop would reduce the strength of the fixer), short wash times without a hypo clearing agent step (even with T-Max), shorter toning times for prints, and TF-4 offers very short fix times.

    Hardening fixers only protect the emulsion when wet, so if you wash sheet film in an open tray after fixing, there may be some advantage to a hardening fixer, but otherwise, I don't really see a need for it. If you decide to tone your negs later to increase contrast, for instance, you'll need to refix first in plain hypo to reverse the effect of the hardener. Without a hardener you can just rinse and tone.
     
  4. jade

    jade Member

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    To me the biggest benefit of using an alkaline fixer like TF-4 is the elimination of both the acid stop and hypo clearing (washing aid) baths. You only need 2 chemicals: developoer and fixer. That's it. Much much less hassle, and fewer things to keep.

    The other benefits in the case of TF-4 is fast fixing time, long lasting, no acid smell and very easy to wash off. The last of these is according to Phtographer's Formulary since I cannot tell myself. Formulary says there's no need to use any washing aid. Luckily I have a local shop that sells TF-4 so no need to pay shipping from mail order. It's the only thing I use now. Cannot imagine going back to acid ever again. You must try or you won't know what you are missing.

    j
     
  5. mobtown_4x5

    mobtown_4x5 Member

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    I just switched to TF-4, question- is the white precipitate at the bottom of the bottle normal?

    Matt
     
  6. Andre R. de Avillez

    Andre R. de Avillez Member

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    I currently use both acid fix (paper) and TF-4 (film), but as soon as my paper fix goes bad, it'll be TF-4 all around (less chemicals to have around, no stop bath spills, etc...).

    I have one question to add to this thread, though:

    Can TF-4 be tested for saturation with Edwal's Hypo Chek?

    I currently use it to test my paper fix, and it works great (I have gone through a batch of fix with it, and the silver recovery proved the Hypo Chek to be right). However, I don't know if it would work with an alkanine fixer. I could wait until my TF-4 is near exhaustion (I have put 78 rolls of film through it, and it should handle 80, so it's dang near it), but if I'd rather know for sure.

    For those unfamiliar with Hypo Chek, you use it by putting two drops into the fixer. If nothing happens, the fixer is good. If a white precipitate forms, it's saturated with silver. Of course, if it doesn't work with TF-4, nothing happening doesn't tell me much.

    Thanks in advance for the help, and sorry for hi-jacking your thread, Thomas.
     
  7. Andre R. de Avillez

    Andre R. de Avillez Member

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    Yes and no. Yes, it's there when you receive the bottle. No it shouldn't be there when you use it. It takes some effort to dissolve it, but it does eventually (dilluting it to working strength may help). Using distilled water may make your life easier (and chemical life longer) as well.

    Good luck,

    André
     
  8. L Gebhardt

    L Gebhardt Subscriber

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    you need to shake the bottle very well before mixing. Once mixed up the precipitate will be gone and you will have nice clear fixer. I imagine if you don't shake the concentrate your first few baches will be weak and future ones will be strong.
     
  9. Ole

    Ole Moderator Staff Member

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    I use alkaline to neutral only - except in the rare cases when I make lith prints and it's important to stop development in a fraction of a second.

    The only drawback with alkaline fixer is that you shouldn't use an acid stop bath...

    I have just finished my first bottle of TF-4, and it's going to be my last. The ammonium smell is far stronger than from my own recipe, without significant increase in speed or capacity.

    :tongue:
     
  10. andrewfrith

    andrewfrith Member

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    TF4 recipe

    Ole..what is your recipe for your TF4 replacement?

    thanks
    -andrew
     
  11. Andre R. de Avillez

    Andre R. de Avillez Member

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  12. Ole

    Ole Moderator Staff Member

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    I've posted it here on APUG before, but I can't remember where. Since I've also posted more than 1100 other posts here, it's going to be difficult to find as well :wink:

    Also, I'm at work in the North Sea right now, and I don't have my darkroom notes with me :sad:

    No, it's not TF-3. It's a simple alkaline sodium thiosulfate formula, modified with a different alkali and addition of ammonium chloride, and a little bit of "tweaking" to keep the smell down...
     
  13. juan

    juan Subscriber

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  15. ongarine

    ongarine Member

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    This is the formula of Ole fixer I saved time ago:
    OF-1 (Ole's Fix numero uno)

    About 1½ cup sodium thiosulfate
    about two spoonfuls (heaped) of sodium sulfite
    a dollop of sodium bicarbonate
    three teaspoons ammonium chloride

    in one liter water - or two.

    Faster than TF-3, less smelly than TF-4, lots cheaper than both.

    Exact measurements still to be determined.

    Daniele
     
  16. Ole

    Ole Moderator Staff Member

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    Ehm - right.

    Translated to real measures, it's about

    200 g Sodium Thiosulfate pentahydrate
    40 g Sodium sulfite
    EITHER 15 ml 10% Sodium metabisulfite solution
    OR 15 g sodium bicarbonate

    Add 50 g Ammonium chloride last - even better if it's diluted in 100ml water first.

    Bicarbonate is more easily available, but should not be used if there is any possibility that the paper/film might be - or become - acidic. The metaborate version can be used with acid stop bath (citric acid), the bicarbonate not.

    Testing is still ongoing :wink:
     
  17. matt miller

    matt miller Subscriber

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    I've been using Ilfostop Odorless Stop, which is Citric Acid based, followed by Ilford Hypam fixer, which is an alkaline (ammonium thiosulfate) fixer. I've been using this for my film. Is this a combo I should not be using? Should I stop using the stop?
     
  18. Ole

    Ole Moderator Staff Member

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    Hypam is a well buffered neutral-ish fix, which can absorb quite a lot of acid before it "tips over".

    Acid stop bath was traditionally used for two reasons: To stop development, and to neutralize the alkali so it wouldn't contaminate the (acid) fixer. Getting too much developer in an acid fixer can have deletorious effects, depending on the composition.

    In general I find a significant loss of highlight detail with acidic rapid fixers, which is absent (or at least very much reduced) if the fixer is alkaline. I use this effect to brighten the highlights of alt. prints - a very dilute acid rapid fixer (1:10 from normal working strength) bleaches van Dykes, salt prints and POP in seconds. I don't want this to happen to negatives - or final prints.

    Getting acid into an alkaline fix is almost as bad - unless you know exactly how the fixer is made, the results are unpredictable. For that reason I have two versions of my recipe, with different ways of obtaining the same pH with a useful buffering effect.
     
  19. mobtown_4x5

    mobtown_4x5 Member

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    Here's a couple more random questions on this for my knowledgeable friends:

    1. Anybody know what fixer would be recomended for P Gainers Vit C developers? I would imagine they are fairly acidic, so would require an acid fix?

    2. I have switched to a water stop, and have been experimenting with letting the film just sit in the first tank/tray of water for a few minutes, to let the shadows continue a bit. Anyone else do this? Have you found it effective, do you reduce dev times to compensate, is there any downside to doing this?

    3. Did we ever get an answer on TF-4 and "Hypo-check"?

    THanks!

    Matt
     
  20. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member

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    2. Yes, this is water bath development. To maximize the effect, transfer the neg from developer to the water bath with minimal agitation, and the developer near the highlights will become exhausted while the developer continues to work near the shadow areas on the neg. The same principle is behind stand development.

    This also works with prints to improve highlight detail with a contrasty neg--a handy trick if you like graded paper and want something in between two grades.
     
  21. Ole

    Ole Moderator Staff Member

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    Why? While vitamin C is Ascorbic acid, it is usually sodium ascorbate that's used. The developer is certainly alkaline, otherwise it wouldn't work at all!

    Use your favorite fix - unless you prefer an acid rapid fix; if you do I'll urge you to try an alkaline one.

    I do it all the time, except when I just wash it quickly. The "important" thing is to get the developer off the surface of the film to minimise contamination of the fixer. I say minimise, not eliminate: You can't get rid of everything.

    I recon that development will continue for a few seconds in the fixer with the 5-second wash I use. Doesn't matter at all. The fixer will counteract the development and stop it very efficiently by removing all active silver halide.

    No, we didn't. But there's no reason it shouldn't work. It even works with my "OF-1" which already contains halides, so it should work just fine with TF-4.
     
  22. psvensson

    psvensson Member

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    The OF-1 formula looks interesting, but why is the alkali necessary? Doesn't it work if it's neutral (or becomes acidic through contamination)?
     
  23. Jorge Oliveira

    Jorge Oliveira Member

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    Ole

    Nice to know the homemade stuff is as good or better than the bottled one!

    Cheers,

    Jorge O
     
  24. Ole

    Ole Moderator Staff Member

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    It works just fine. But I prefer to have a buffered solution of known pH, as it makes everything a lot more predictable. Both alternatives give a pH of about 8.5, which is just enough to be stable and wash out easily.

    I know from experience that acidic ammonium fixers bleach highlights in prints, and I assume they also lose shadow detail in film. I have also established to my own satisfaction that this does not happen with alkaline fixers, at least not without ridiculously long fixing times or very sensitive processes (read: van Dyke).

    That's why I put alkali in it.
     
  25. psvensson

    psvensson Member

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    Thanks, that's interesting. I've saved the formula. I've tried using plain sodium thiosulfate + sulfite. That worked fine for paper and Tri-X, but wouldn't quite fix Delta 400 to satisfaction, so it's interesting to see a nice and simple formula for rapid fix.
     
  26. Ashfaque

    Ashfaque Member

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    Sorry to post on such an old thread - I'm just a novice.
    So, in summary, I should not be using any acidic stop bath if I am planning to use:
    (1) an alkaline fixer, in general - for e.g., TF-4, TF-5, Moersch ATS Alkaline Fixer, etc.
    (2) an alkaline fixer to keep the stain as much as possible, resulting from any staining developer (PMK, Pyro-HD, etc.)

    Another possibly dumb query: is there a non-acidic stop bath? I am aware of 'Ilford wash method' as an alternative to using stop bath chemicals.

    Best regards,

    Ashfaque