how many 8x10 papers can a liter of F-6A fixer process?

Discussion in 'Darkroom Developing and Printing' started by Steven Woody, Aug 31, 2006.

  1. Steven Woody

    Steven Woody Guest

    thank you.

    -
    woody
     
    Steven Woody, Aug 31, 2006
    #1
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  2. Steven Woody

    darkroommike Guest

    Nice straight answer? It depends.

    Here are the variables to consider:
    Type of paper, FB or RC
    One bath fixing or two.
    And the water you use to mix the fixer.

    The best way to find your answer is to test yourself in your own
    darkroom, Vestal in his book, The Art of Black and White Enlarging, has
    a good test sequence.

    If just starting out and no time to test, here's what I would do for an
    FB sequence. And since I am not using f6A this is literally what I would
    do until I had time to test:

    Use the two bath method. Mix two four liter batches of F-6a. Calculate
    Kodak's recommended usage for four liters of F-6 (if I can't find one
    for F6-a (always a problem when using modified formulas)) and then
    DIVIDE BY TWO. Let's say that the number of prints per 4 liter bath
    equals 100.

    Discard fix bath one after one hundred prints, pour bath two into the
    bottle labeled fixer one and mix another four liters of fixer two.
    Discard both fixers every thirty days. This is very conservative
    practice and will go a long ways to ensuring your prints will be around
    in good shape a long time.

    Note it's fun to experiment with formulas but if your not doing 100
    prints a month you'd probably be better off buying prepackaged fixers
    and not mixing your own.
     
    darkroommike, Sep 1, 2006
    #2
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  3. Kodak F-6a is a stock hardener solution for fixer formula
    F-6. If you have F-6a, it is not a complete fixer. F-6 is
    given as an oderless fixer.
    Since the amount of thiousulfate in F-6 is the same as in
    F-5, which is what packaged Kodak fixer is, the capacity is
    about the same. The capicity depends on how well fixed the
    prints are to be. For archival purposes the capacity of a
    single fixing bath is very limited, Ilford states its no
    more that about 10 8x10 prints per _gallon_. Kodak gives the
    capacity as 100 8x10 sheets per gallon but that is probably
    for "commercial" use with a 25 year expected lifetime. By
    using two successive baths the archival capacity can be
    increased by about 10 times, that is, to the same amount as
    for the less permanent commercial standard.
    The degree of fixing can be tested with either of two
    simple test formulas. One is a 1% solution of Sodium
    Sulfide, the other is a 1:9 dilution of Kodak Rapid Selenium
    Toner. The toner test solution will fail if there is a lot
    of residual hypo in the print (must be well washed before
    testing). Place a drop or two on a clear area of the print.
    Allow it to stand for about 2 minutes, blot off and examine
    for any stain. There should be no detectable stain with
    either test. The prints to be tested should be wet not have
    surface moisture. Its best to use a small sample of paper
    processed along with the prints because any stain from the
    test solution can not be removed. If a stain appears the
    prints should be refixed in fresh fixer.
    Someone else has given instructions for the two bath
    system of fixing. You can also find this is several Kodak
    publications.
     
    Richard Knoppow, Sep 1, 2006
    #3
  4. Steven Woody

    darkroommike Guest

    What Woody is referencing is the Ansel Adams version of F-6, not the
    hardener formula. Maybe to eliminate confusion it should have been
    named F-6AA. It's just F-6 with less alum, see:
    http://www.jackspcs.com/f6a.htm
     
    darkroommike, Sep 2, 2006
    #4
  5. Steven Woody

    Steven Woody Guest

    yes, what i said is the Adams's version of F-6, and it was said as f-6a
    in jack's site.

    i am processing 8x10 RC papers.
     
    Steven Woody, Sep 2, 2006
    #5
  6. Steven Woody

    Lloyd Erlick Guest


    September 2, 2006, from Lloyd Erlick,

    Is hardener really necessary for this type of
    material??

    F6 minus the hardener ... minus the acetic
    acid (needed because of hardener) ... leaves
    the fixer Adams called 'plain fixer' - in the
    appendix to 'The Print'. Fixer can't get
    cheaper, easier or quicker to prepare.

    But the original poster seems to be trying
    various materials and formulas for
    educational purposes ... so Kodak fixer F5
    would be in order. The formula usually
    specifies a gallon, but only a liter or even
    half a liter is enough (for educational
    purposes, that is ...). The smell of F5 is
    powerfully obnoxious (no wonder they called
    it darkroom fumes). It's very interesting how
    F6 eliminates the smell! If one prepares F6
    slightly differently (add acid *after* the
    alkali) from the usual presentation of the
    formula (acid added to the mix before the
    alkali) there is no smell at all.

    Both F5 and F6 are of academic interest. Most
    current production materials (the films and
    papers, RC and FB, found in a 'usual'
    darkroom like mine) require no hardener. In
    addition, I prefer a low-capacity fixer
    because with relatively low throughput in my
    darkroom, it takes too long to exhaust a
    commercial, so-called, rapid fixer.

    I like to make up fixer with distilled water,
    so no sequestering or chelating agent is
    necessary, either.

    regards,
    --le
    ________________________________
    Lloyd Erlick Portraits, Toronto.
    website: www.heylloyd.com
    telephone: 416-686-0326
    email:
    ________________________________
    --
     
    Lloyd Erlick, Sep 2, 2006
    #6
  7. An unfortunate confusion. The amount of hardener does
    not matter, it takes no part in the fixing process. In fact,
    it can be left out altogether, Kodak F-24 is a non
    hardening, low odor formula.
    The capacity of a fixing bath depends on the amount of
    thiosulfate in it. It takes about three thiosulfate ions to
    convert one silver halide molecule. Ions which become bound
    to halide are no longer available to convert more. While one
    can test the hypo bath for dissolved silver by means of the
    simple Potassium Iodide test it is indirect. Testing a print
    or test paper using a solution which reacts directly on the
    remaining halide is superior.
    Several years ago Michael Gudzinowicz, who is a Phd
    chemist, wrote a complete description of the fixing process
    to this list. Google may be able to find it. The fixing
    process is not simple, but rather a chain of reactions each
    resulting in the halide complex being more soluble. The
    fixer must be prett fresh to complete this chain and allow
    the unused silver halide to be completely washed out of the
    emulsion. Two bath fixing is helpful because the first bath
    does most of the work leaving the second bath relatively
    fresh to clean up any remaining incompletely converted
    halide.
    Most conventional fixer formulas are acid because they
    are intended to contain a hardener. It is the hardener which
    must work in an acid bath, hypo works equally well in acid,
    alkaline, or neutral solutions. However, the odor associated
    with hypo is from the acid. The acid would decompose the
    thiosulfate very quickly so a relatively large amount of
    sulfite is added. Some sulfite decomposes releasing Sulfur
    dioxide gas which has a sharp odor and can be very
    irritating. By eliminating the hardener the pH can be
    whatever one wants. A somewhat acid bath is still desirable
    to prevent carried over developer from being active in the
    fixing bath but much less acid is needed for this. Neutral
    fixing baths have very little odor but an acid stop bath can
    not be used so film or paper must have a short and rather
    rapid wash between the developer and fixing bath. Alkaline
    fixing baths, which are currently popular, have no advantage
    over a neutral bath.
     
    Richard Knoppow, Sep 3, 2006
    #7
  8. Steven Woody

    Lloyd Erlick Guest



    low odor formula.


    September 4, 2006, from Lloyd Erlick,

    I beg to differ. In fact, I'd say anyone who
    mixes F-24 in a sink and holds their head
    over it will smell it quite prominently. It
    smells like good ol' acid fixer. The same is
    true of the version that specifies citric
    acid instead of acetic.

    I know many long-term sources claim F-24 is
    low odour, but it only needs to be mixed to
    prove it is far from it.

    Low odour fixers are easiest to make sans
    acid, although F-6 is an odorless, acid
    fixer. But it's acid because it's a hardening
    fixer, and who needs hardener? Without
    hardener and acid, F-6 is pretty much Ansel
    Adams' 'plain fixer' (water, sulfite and
    thiosulfate). Probably a member of the
    'neutral' category.

    regards,
    --le
    ________________________________
    Lloyd Erlick Portraits, Toronto.
    website: www.heylloyd.com
    telephone: 416-686-0326
    email:
    ________________________________
    --
     
    Lloyd Erlick, Sep 4, 2006
    #8
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