Silver flouride - has it ever been used In Photography?

Discussion in 'B&W: Film, Paper, Chemistry' started by jm94, Aug 31, 2012.

  1. jm94

    jm94 Member

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    This might seem an odd question, searches on the web yielded zilch, my curiosity has been bugging me with this for a while. Seeing as silver halides are very photosensitive, does silver flouride exercise the same property? I know Flourine likes to bond tightly to whatever it can, and seeing as light hitting silver halide crystals has to yield say 4 atoms of free silver to be developable, freeing the bromine atom is this why I have never seen it used? If it is photosensitive like the others, is the strength of the F - Ag bond tight enough that one would need ridiculous exposure times to make much change at all?or maybe even not photosensitive due to the strength of the bond? This I only assume due to the nature of Flourine being the most electronegative of all the elements and it's tendency to form unreactive, tight bonds to anything making Flourine compounds,even glass!

    Hopefully someone can shed light on this!

    Jacob
     
  2. railwayman3

    railwayman3 Member

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    Without going into detailed chemistry (and ignoring potential light sensitivity), it seems that the various forms of silver fluoride are either water-soluble or actively react with water. This would seem to preclude any uses in general photography?

    The bromide and iodide are, of course, insoluble for practical purposes, hence their choice for emulsion use?

    (Wikipedia gives a lot of technical info on silver halides. :smile: )
     
  3. jm94

    jm94 Member

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    Ahh that would explain everything! Would wash off / out of the emulsion during development or presoak. The Internet yielded very little with regards to light sensitivity but i had overlooked that fact. Thanks :smile:
     
  4. holmburgers

    holmburgers Member

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    From here, http://www.apug.org/forums/viewpost.php?p=1103794

    Interesting question. Regarding water-solubility, consider Daguerreotypes. Water doesn't even figure in to these; so maybe there's some way??
     
  5. TheFlyingCamera

    TheFlyingCamera Membership Council Council

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    not true mon frere. You still have a water-based fixing bath, a post-fix wash in distilled water, and the gilding stage is also 5% gold chloride in an aqueous suspension. Plenty of opportunities to dissolve the light-sensitive silver halide layer were it water-soluble.
     
  6. jm94

    jm94 Member

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    As I now realise being water soluble rules it out of photographic processes, but I do not know how sensitive if at all, to light. Flourine by nature provides stable bonds to most elements. Search engines yield little on this compound.
     
  7. Gerald C Koch

    Gerald C Koch Member

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    Silver fluoride is a powerful oxidizing agent which reacts violently with water releasing ozone and fluorine and forming hydrogen peroxide. Even though it is light sensitive I think this explains why it isn't used. Even though fluorine is in the same family as chlorine, bromine, and iodine its chemistry is very different. This is true for the rest of the elements in the first row of the periodic table. They are all different from the rest of the elements in their families.

    Astatine is radio-active and very rare in nature. Add to this the fact that its most stable isotope has a half-life of only 8.1 hours.
     
    Last edited by a moderator: Aug 31, 2012