Rapid fixers - chloride X sulphate

Discussion in 'Darkroom Developing and Printing' started by Jorge Omar, Feb 4, 2004.

  1. Jorge Omar

    Jorge Omar Guest

    Hello,

    Thre are rapid fixers made by mixing hypo with ammonium chloride or
    sulphate (Kodak's F-7 and F-9).

    It just happens that Kodak F-7 uses 50g of chloride, F-9 uses 60g of
    sulphate.

    The molecular weight of chloride is 53.49g and of sulphate is 132.14g.

    Doesn't it looks like there is too little sulphate in F-9?

    Thanks,

    Jorge
     
    Jorge Omar, Feb 4, 2004
    #1
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  2. Sulphate is not what matters; it is the ammonium ions that count. There
    is only one ammonium ion in amminium chloride, whereas there are two in
    ammonium sulphate.
     
    Jean-David Beyer, Feb 4, 2004
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  3. Jorge Omar

    Jorge Omar Guest

    Thanks, Jean-David.
    I've almost forgotten my chemistry classes; taking the 2 NH4 in account
    they are very much equivalent.

    Jorge
     
    Jorge Omar, Feb 4, 2004
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