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. OP
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    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.
     
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    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 Subscriber

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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.
     
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  8. cliveh

    cliveh Subscriber

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    As pdeeh has kindly pointed out this thread and so as not to highjack the other one, I would suggest that water solubility is not a barrier for producing an image using a silver fluoride compound. You can expose a photogenic drawing and then re-photograph it, or scan it without subjecting it to any processing.

    Can anyone suggest some starting points for experimenting with this halogen that is relatively safe?
     
  9. NedL

    NedL Subscriber

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    Our water is supplied by a well, rather than a fluoridated city water supply. When my daughter was little, her dentist gave her little sodium fluoride tablets. I see that sodium fluoride is available on Amazon for about $2/oz.

    It seems to me that water solubility doesn't "rule out" AgF as a photographic agent per se... If it did act like other halogens, and if a silver image forms, then it might be possible to fix the image just by washing out the remaining AgF with water. I think what Jerry wrote just above is the real reason it's not used in photography.

    I'd be very cautious about trying this. If AgF forms from NaF and AgNO3, then it could react with moisture in the paper and release fluorine. Seems like it's not something to mess around with to me.
     
  10. cliveh

    cliveh Subscriber

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  11. Rudeofus

    Rudeofus Subscriber

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    When I had a brief stint in a semiconductor facility, we went through multi hour safety training before we were allowed to work in there. The safety guys were responsible for a large institution, which had an ME department (think mills and lathes), a EE department (think high voltage equipment) and a chem department. They strongly assured us, that the most horrible accidents they every encountered during their decade long career were accidents involving Hydrofluoric Acid. Alkali fluorides fall under the exact same category, since Fluoric Acid is a weak acid, released quickly in neutral or acidic environment.

    I am lucky enough to have never been or seen the victim of a Fluoride related accident, and encourage everyone else here to follow suit. Whatever its photographic promise may be, it's simply not worth it by any stretch of imagination.
     
  12. nworth

    nworth Subscriber

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    Koch gave perhaps the best explanation. Soluble fluorides are also intense and often subtle poisons.
     
  13. NedL

    NedL Subscriber

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  15. Martin Rickards

    Martin Rickards Member

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    Why not try silver astatide if your interested in silver halides?:wink:
     
  16. Agulliver

    Agulliver Member

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    Most fluoride salts, including silver fluoride and the sodium fluoride which is probably in your toothpaste and might be in your water....are pretty nasty and very poisonous. Quantities in toothpaste and water are very small to get the advantages without hurting or even killing people. If you thought chlorides and bromides were bad, you don't want to mess with fluorides.

    Heck...I'll happily make my own potassium dichromate bleach and use it without gloves...but I won't go anywhere near fluorides.
     
  17. pdeeh

    pdeeh Member

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    I use a specially prescribed high-fluoride toothpaste (2800ppm) and have idly considered coating some paper with it and AgNO3 to see what happens.
    But then you can pretty much coat any old bit of paper with AgNO3 and end up able to make an image. It readily forms light-sensitive compounds with all sorts of things. (Think what happens when you get it on your skin)
     
  18. AgX

    AgX Member

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    Moreover, AgNO3 itself is already light sensitive.
     
  19. Martin Rickards

    Martin Rickards Member

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    Silver sulphadiazine is used topically for burns and blackens in sunlight.
     
  20. NedL

    NedL Subscriber

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    Many old instructions imply that something called "silver albuminate" is a light sensitive component of an albumen print.
    I have no idea what that is but maybe some kind of organic silver salt is formed when AgNO3 is mixed with albumen.
     
  21. jnanian

    jnanian Advertiser Advertiser

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  22. avb

    avb Member

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    See US Patent 3,537,855 "Photosensitive Silver Fluoride Element" (1970 assigned to Polaroid) for an example of using AgF. The silver is actually fluorinated in the process of making the substrate.

    1 ppm NaF is typical of drinking water Remember that 1 ppm NaF means 0.000001 g of NaF in 1 g water.
    (The NaF tablets are not pure sodium fluoride!)

    A much higher concentration of NaF solution, for example 0.5 M NaF, has health effects per MSDS (same as HF description):
    Consult a physician. Show this safety data sheet to the doctor in attendance.Move out of dangerous area.Hydrofluoric (HF) acid burns require immediate and specialized first aid and medical treatment. Symptoms may be delayed up to 24 hours depending on the concentration of HF. After decontamination with water, further damage can occur due to penetration/absorption of the fluoride ion. Treatment should be directed toward binding the fluoride ion as well as the effects of exposure. Skin exposures can be treated with a 2.5% calcium gluconate gel repeated until burning ceases. More serious skin exposures may require subcutaneous calcium gluconate except for digital areas unless the physician is experienced in this technique, due to the potential for tissue injury from increased pressure. Absorption can readily occur through the subungual areas and should be considered when undergoing decontamination. Prevention of absorption of the fluoride ion in cases of ingestion can be obtained by giving milk, chewable calcium carbonate tablets or Milk of Magnesia to conscious victims. Conditions such as hypocalcemia, hypomagnesemia and cardiac arrhythmias should be monitored for, since they can occur after exposure.
     
  23. If silver fluoride was useful in photography then it would have been used in the last almost 200 years.
     
  24. cliveh

    cliveh Subscriber

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    Then why did polaroid take out a patent? (link in my post 10)
     
  25. AgX

    AgX Member

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    Well, they may have tried just to keep a foot in the door.
    Most patents ever applied were economical unsuccessful.
     
  26. avb

    avb Member

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    Polaroid took out a patent on a specific method for making AgF substrate. I think a patent on just using AgF would be considered too obvious to be accepted by the patent office.