TF-3 alkaline fixer, sodium sulfite solubility problem

Discussion in 'Darkroom Developing and Printing' started by Shakti V., Oct 11, 2006.

  1. Shakti V.

    Shakti V. Guest

    I just mixed a TF-3 fixer. Here is the formula I used:

    * Ammonium thiosulfate (57-60%) 800 ml

    Sodium Sulfite (anhy) 60 g

    ** Sodium Metaborate 5 g (50ml of 10%sodium metaborate/L)

    Distilled water to make 1000 ml

    ~ . ~ . ~ . ~


    * To make ammonium thiosulfate: I mixed ammonium chloride 600g + sodium
    thiosulphate(penta) 1406g [900g for anhy ; divide by 0.64 (900/0.64), to get
    grams in penta] in 1.5 L of water. I used 800ml only per 1Liter of fixer.

    ** I made sodium metaborate from Borax 69g + 14.5g NaOH (tech grade,flakes)
    in 1L of water, for a 10% solution of sodium metaborate (100g/L); I used 50ml
    to get 5g.

    There was a very thin layer of white substances/flakes floating on top of the
    finished solution. Also, the sodium sulfite (photo grade, in white powder
    form) was very hard to dissolve. I heated the solution to 50degC before
    adding sodium metaborate, to help dissolve the sodium sulfite, but still it
    doesn't dissolve completely. There is still a considerable amount of sodium
    sulfite at the bottom of the solution up to now. Is this occurence normal for
    TF-3 fixer?

    I notice that the sodium sulfite in this formula is thrice the usual amount
    per liter, which is normally 15g/L. I assume that that is the reason why the
    sodium sulfite was incompletely dissolved. What else could I do to dissolve
    the sodium sulfite? Or should I just let it stand in the solution? Will it
    harm the fixer?

    If you notice any mistakes in the formula or the method, please post the
    corrections here.

    Thanks again to this wonderful forum.

    Footnote: I mix ammonium thiosulphate and sodium metaborate from scratch
    because the chemicals are not available here in my country.
    I wouldn't buy ready-made fixer now because I am at a phase where I want to
    learn to mix my own chemicals.
     
    Shakti V., Oct 11, 2006
    #1
    1. Advertisements

  2. Shakti V.

    Rod Smith Guest

    I'm no chemist, but I'd imagine that by mixing ammonium chloride and
    sodium thiosulfate, you'd get something in addition to ammonium
    thiosulfate -- probably sodium chloride. This could well be part or all of
    the cause of the problems you relate later in your post.
    If you can't get ammonium thiosulfate but still want a rapid fixer, you
    might want to give Agfa 304 a try:

    water (125F/52C): 750ml
    sodium thiosulfate: 200g
    ammonium chloride: 50g
    potassium metabisulfite: 20g
    water to make: 1l

    This is Anchell's (_Darkroom Cookbook, 2nd Edition_) formula #123. Anchell
    says to fix paper for 3-5 minutes and film for 3x the clearing time. (I
    don't know why these values.) The formula does what you were trying to do
    -- it makes ammonium thiosulfate in solution from sodium thiosulfate and
    ammonium chloride. It was presumably designed with the sodium chloride (or
    whatever the reaction byproduct really is) in mind, though. I've never
    used this formula; I'm just passing it on because I remember it from the
    book.

    In what country are you located? Perhaps you could track down other local
    photographers to combine resources for obtaining necessary photochemistry.
     
    Rod Smith, Oct 12, 2006
    #2
    1. Advertisements

  3. Shakti V.

    Tom Phillips Guest

    3x the clearing time would seem way too long
    and also might begin to bleach out the silver.
    2x is pleanty in my experience...
     
    Tom Phillips, Oct 12, 2006
    #3
  4. Shakti V.

    darkroommike Guest

    Clearing times in 'rapid" fixers. My rule of thumb is 2x for slow speed
    or conventional materials and 3x for modern emulsions like T-Max and
    fast emulsions like HP-5 or Tri-X. I've not tested this in a while
    since my film volume has slipped so low I now use liquid fixer, one
    shot, at paper strength, for fixing film with constant agitation.
    darkroommike

     
    darkroommike, Oct 12, 2006
    #4
  5. Shakti V.

    Digitaltruth Guest

    All of the TF- formulas, including the proprietary formula for TF-4,
    have solubility and precipitation problems, so mixing can be difficult.
    Nonetheless, the chemicals should go back into solution and the
    formulas will work.

    --Jon Mided

    Digitaltruth Photo
    http://www.digitaltruth.com
     
    Digitaltruth, Oct 12, 2006
    #5
  6. Shakti V.

    Tom Phillips Guest

    For Tmax one should fix until there is no
    dye left (i.e., until fb+f areas show no
    purple tint and are clear.) Whether it's
    2x or 3x I don't know but this indicates
    complete fixing, at least for Tmax films.
     
    Tom Phillips, Oct 12, 2006
    #6
  7. Tom Phillips a écrit :
    I too fix more T-grain films than "normal" ones but I don't think you
    need to overfix just to remove the purple tint.
    If you use a washaid, I just use plain sodium sulfite @ 20gr/l, before
    the final wash, the tint is removed very easily.

    Claudio Bonavolta
    http://www.bonavolta.ch
     
    Claudio Bonavolta, Oct 13, 2006
    #7
  8. "Tmax Pink" washes out much faster if the wash-aid
    and wash water are ~75F. TMax films are [or so I
    think I remember hearing] less sensitive to higher
    temperatures.
     
    Nicholas O. Lindan, Oct 13, 2006
    #8
  9. Shakti V.

    Tom Phillips Guest

    Not talking about over fixing (hard to do anyway...)
    The purple is a sensitizing dye that can also
    bind to silver halides and silver thiosulfate
    residues in the emulsion. If the purple/magenta
    color is very light it will wash out in Hypo
    Clear. If it's darker and more pronounced your
    film isn't being fixed long enough. I typically
    fix Tmax for 6 minutes in fresh fix and in my
    experience this isn't too long a fixing time for
    Tmax films. The stain is usually gone after 5-6
    minutes in fresh fix. As the fixer gets saturated
    my fixing times can go to 7-8 minutes before
    discarding. Meaning if the purple isn't gone in
    about 7/7.5 minutes I discard the fixer.


    Kodak pub. F-4016 also states:

    Your fixer will be exhausted more rapidly with these films
    than with other films. If your negatives show a magenta
    (pink) stain after fixing, your fixer may be near exhaustion,
    or you may not have used a long enough time. If the stain is
    slight, it will not affect image stability, negative contrast, or
    printing times. You can remove a slight pink stain with
    KODAK Hypo Clearing Agent. However, if the stain is
    pronounced and irregular over the film surface, refix the film
    in fresh fixer.
     
    Tom Phillips, Oct 14, 2006
    #9
  10. Shakti V.

    dan.c.quinn Guest

    RE: Tom Phillips wrote:h
    Rapid fixers are no longer "rapid" and capacity is much
    reduced due to the iodide. The ammonium ion has little affinity
    for silver in the presence of iodide. In effect the fixer becomes
    a sodium thiosulfate fixer. The thiosulfate ion does have the
    necessary affinity for silver in the presence of iodide to do
    the job.
    Ammonium and sodium silver thiosulfate complexes are
    soluble. Impurities in the water which form insoluble compounds
    with the thiosulfate complex may be another source of the pink.
    Such compounds can precipitate in the emulsion along with
    the dye. Test using only distilled water start to finish. Dan
     
    dan.c.quinn, Oct 14, 2006
    #10
  11. Shakti V.

    Tom Phillips Guest

    Have to wonder why they call it Rapid Fix, then.
    I seem to get about the stated capacity Kodak
    lists. In any case I use it mainly due to it's
    ease of use (i.e., liquid concentrate.) And since
    I quit using powdered sodium fixers about 15 years
    ago I have no comparison data on rapid vs.sodium
    thio efficaciousness with various fixing times.

    The ammonium ion has little affinity
     
    Tom Phillips, Oct 14, 2006
    #11
  12. Shakti V.

    Tom Phillips Guest


    Here's an interesting post from Richard 3 years ago...

    Subject: Re: Rapid Fixer Questions
    Date:Tue, 29 Apr 2003 20:57:47 -0700
    From: "Richard Knoppow" <>

    Ammonium thiosulfate fixes out faster than sodium at the
    same molar concentrations. However, the difference in speed
    depends on the emulsion. Ammonium fixer is most effective
    with emulsions containing a lot of silver iodide. That
    includes film emulsions generally but especially fast
    emulsons and tabular grain emulsions like Kodak T-Max,
    Ilford Delta, and Fuji Acros. Kodak Tri-X is also a very
    iodide emulsion which tends to fix out more slowly than
    other films.
    For these ammonium fixer is quicker and gives more
    assurance that the emulsion will be completely fixed out.
    For paper type emulsions there is less difference between
    sodium and ammonium although the ammonium fixer is still
    faster. However, _acid_ ammonium fixer has a tendency to
    bleach very fine metallic silver grains. These are plentiful
    in paper emulsions, which are excedingly fine grain compared
    to film. For that reason, and because paper fixing times are
    short whichever fixer is used, sodium fixer is to be
    preferred for paper.
     
    Tom Phillips, Oct 14, 2006
    #12
  13. Shakti V.

    dan.c.quinn Guest

    Tom Phillips
    With iodide present a rapid fix in effect becomes a more nearly
    sodium thiosulfate fix. That would have been a better way to put it.
    The slow down with rapid and decrease in capacity with both S
    and A fixers is due to the extreme insolubility of silver iodide.
    Thiosulfate forms a bond of such strength with silver that it
    can form an in solution complex. The ammonium ion will
    not do that to any meaning full extent although it's
    presence does quicken the process some little.
    I've no argument with an ammonium fixer being more rapid
    and in ALL cases, film and paper. How much faster? Dan
     
    dan.c.quinn, Oct 15, 2006
    #13
  14. Shakti V.

    Tom Phillips Guest

    Yes, that's a little clearer. Thanks.
     
    Tom Phillips, Oct 15, 2006
    #14
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.