Potassium cyanide fixer

Discussion in 'B&W: Film, Paper, Chemistry' started by alexhill, Jun 7, 2010.

  1. alexhill

    alexhill Member

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    I'm shooting a homemade dryplate emulsion and I'm interested in making ambroypes. So instead of my sodium thiosulfate fixer, could I use a potassium cyanide fixer to cause the silver to lighten?

    Also, can a potassium cyanide fixer be reused? Does a potassium iodide hypo check solution work for checking for exhausted fixer?

    Does a 2 min wash with 3 exchanges of water remove enough pyro so that i won't kill my self with chlorine gas? I intend to fix outdoors anyways..

    Currently I'm not fixated on historical accuracy, is there another way to lighten the silver deposits?
     
  2. Jim Noel

    Jim Noel Member

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    Bleach them.
    You need to check with the experts on the collodion site.
     
  3. alexhill

    alexhill Member

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    I'm going out on a limb and guessing your talking about using bichloride of mercury as a bleaching solution? Anyone got a link to a recipe?


    heck, anyone have a link to where I can buy either chemical as in individual?
     
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  4. MikeSeb

    MikeSeb Member

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    Out of curiosity, how dangerous is KCN to handle? This is exactly the lethal, prussic-acid stuff, isn't it?
     
  5. alexhill

    alexhill Member

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    Everything I've read says "wear gloves" and make sure as hell you don't get acid in it. Obviously you don't want it in any cuts. A side note, A google search turned up lots of depressing links on KCN, in particular a suicide help forum where everyone was recommending its use.

    And thats why I can't find a store to sell it to me :sad:
     
  6. Photo Engineer

    Photo Engineer Subscriber

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    There is no chlorine involved, just HCN or HydroCyanic Acid or Prussic Acid. It is lethal in very tiny doses and can be easily absorbed through the skin. It smells like almond oil and is rather pleasant as the last thing you smell!

    Use it with great caution.

    It is not normally used to fix normal Silver Halide emulsion coatings nor is it easily tested for exhaustion AFAIK.

    BTW. Been nice having you here on APUG. Best wishes. :wink:

    PE
     
  7. alexhill

    alexhill Member

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    :smile: I've been having a great time on here

    So on my to find list I have three options:
    HydroCyanic Acid(can't find any one who sells it)
    potassium cyanide (10% solution, not sold to individuals)
    Mercury(II) chloride (5% solution, not sold to individuals)

    How do those blackpaws do it?
     
  8. Kirk Keyes

    Kirk Keyes Member

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    Hydrocyanic acid is very toxic - it will give off vapors that are toxic as well. Stay a long way from it.

    You should be able to find potassium cyanide. It's stable as a powder, although the bottles I've gently sniffed after opening do not have a pleasant smell to them... Keep it away from both strong and weak acids. Even vinegar/acetic acid is strong enough to evolve poisonous cyanide fumes from it.
     
  9. jnanian

    jnanian Advertiser Advertiser

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    where are you going to dispose of your wash water and cyanide??
    you are in NH and i imagine if you are out of the southern and central cities you
    are on a well and septic system.
    i would be very careful with this deadly substance, not only when you are actually in contact with it,
    but afterwards if you don't dispose of it properly and you contaminate your ground water and everyone in your area's ground water.

    years ago gasworks used to use cyanide as part of the coal gasification process. they dumped it on site
    and when the gasworks were vanished and topsoil was put on the sites filled with cyanide and other toxins
    lawns were blue and there were HUGE instances of cancers, and it was all linked to cyanide.

    i would make a negative internegative and
    just make contact print onto your dry plates using the chemistry you are already using,
    that is what i used to do when i made glass positives it was easy.
    it might be an extra step ( internegative ) but in the end you won't wake up i dead.
     
  10. alexhill

    alexhill Member

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    I will be disposing of this as I do with all the other photo chemicals. I'll be taking the hazardous waste to disposal day.

    I thought I'd share where I found a source to buy KCN Without shipping its 30$ for 25 grams or 500 grams for 80. I'd like to split an order with someone else from NH

    I'm going to give this a try.
    Fixer

    1. 5 grams Potassium Cyanide

    2. 500 mls H2o (distilled)

    *Do not mix this mixture with the developer at any time as a dangerous gas will occur. Use fixer many times until fixing properties are gone. Place the developed and rinsed plates into the fixer smoothly. Watch the plate so as not to over fix. It will become blue streaked with over fixing. When plate is fixed, rinse and wash plate in fresh water to remove residue of Fixer. Dry the plate in a heated cabinet if possible.
     
  11. smieglitz

    smieglitz Member

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    Not everyone can detect the almond smell so that can't be used as a measure of safety.

    To the OP: if you want to make an ambrotype, why not just learn wetplate? I suspect it is easier than dryplate although perhaps not as convenient.

    KCN is optional in wetplate. Personally, I use ammonium thiosulfate to fix ambrotypes.
     
  12. desertrat

    desertrat Member

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    I'm pretty sure Sigma-Aldrich doesn't sell to individuals.

    This from their Order Center page:

    "Ordering Instructions and Help

    Due to the hazardous nature of many of the products we sell, all requests to order / request quotes on-line are reviewed to verify that you are part of an organization that is an existing Sigma-Aldrich customer.

    If your organization has not ordered from us in the past or you have an immediate need to order, please call your Local Sigma-Aldrich Office. Otherwise, complete the request process on-line using the My Profile form. These requests are usually reviewed and completed within two business days."

    I'm not exactly timid about chemicals, but potassium cyanide is one I will probably never order. Hydrocyanic acid is so dangerous, I believe it's shipped in compressed gas cylinders instead of glass bottles, even though it's liquid at room temperature.

    Link:

    www.matheson-trigas.com/pdfs/msds/MAT11160.pdf
     
  13. patrickjames

    patrickjames Member

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    I don't understand the guys that drive around with this stuff in their car. Not only could you Darwin yourself, but you could take others with you. Just so you can make images? ("you" is used figuratively, not anyone in this thread, that I know of anyway)
     
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  15. alexhill

    alexhill Member

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    I appreciate the warnings, and I am aware of the dangers posed with this and all of the chemicals I use. For every hour I am touching a camera, I am reading 4-10 about what I plan to do. I do not crassly run into any project. If you do your research, and are careful, then there is no reason why you should fear KCN or anything else.

    heres a story on fear: I am scared of heights. Anything over about 6 feet will get me nervous. I also really like to multi-pitch rock climb. Being 400 feet up on hand placed (trad) gear is common. How do I translate that fear into something useful? I make damn sure my knots are tied right.
     
  16. mhcfires

    mhcfires Subscriber

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    They used to use this stuff in the gas chambers before they decided to use lethal injection. KCN is ruff stuff, I would use some of the other methods suggested. Safety is everyone's business.
     
  17. Barry S

    Barry S Member

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    I hope your car runs on unicorn tears, since gasoline is toxic and highly flammable. :smile: Seriously, KCN can be handled safely. It can be dangerous, but so can the stuff under your sink and a rusty garden rake. I prefer KCN as a wet plate fix for a number of reasons and with some simple precautions. the risks can be minimized.

    At this point, the only company I know of selling KCN to individuals is Chemsavers You may get lucky and find some cheap platers grade KCN at a local electroplating company, but otherwise, it's become very expensive and difficult to find.
     
  18. JPD

    JPD Member

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    :sad:
     
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  19. alexhill

    alexhill Member

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    Thanks Barry, I was having a tough time replying to this with out trollin'. I prefer helpful conversation rather than gloom and doom warnings. Thanks for the link. I'm going away for 2 months soon and I've got a place I'm going to try in the fall, that link will be my backup :smile:

    Just curious, what are you persuasions/work flow when working with KCN
     
  20. Barry S

    Barry S Member

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    Alex, the precautions I use with KCN are similar to how I handle other hazardous wet plate chemicals like Cadmium Bromide. It's just a matter of slowing down, having respect for the chemicals, and taking some very simple precautions.

    Storage--Hazardous chemicals are stored in a safe area and well-labeled, away from children or anyone else that might be curious.

    Planning--Before I retrieve and open any hazardous chemical, I know exactly how much I need and how I'm going to handle it. I have a scale, weigh boats, spoons/spatulas, and beakers ready.

    Respirator--I use a respirator with the appropriate cartridges to avoid breathing any aerosolized powders. KCN comes in large hygroscopic crystals, so this isn't a big issue, but I notice my cartridges absorb the bitter almond smell, so that helps.

    Nitrile Gloves--I bought a case of disposable nitrile gloves and I always use them when preparing chems and practicing the wet plate process.

    Safe Usage-- I try not to splash or drip chemicals and recommend a separate fixer box for KCN as opposed to a tray. I keep plenty of paper towels and lab wipes on hand to pick up drips or small spills.
     
  21. trip_wt

    trip_wt Member

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    Out of curiosity, how are the properties of cyanide fixers different from modern fixers? What advantages do they have?
     
  22. Photo Engineer

    Photo Engineer Subscriber

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    Barry;

    You forgot one.

    Safe Disposal! All solution and wipes and gloves must be disposed of as extremely hazardous waste. Even the final wash water is hazardous until all cyanide is washed out of the coating.

    PE
     
  23. Shangheye

    Shangheye Member

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    Is using Sodium Thiosulpahte so bad? I know that the image is lighter, but why can that not be dealt with through exposure? Seems a lot less hassle..? K
     
  24. alexhill

    alexhill Member

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    My interest is in the silver itself being lighter. This is important in having sweet ambrotype where the negative appears as a positive because of the contrast between the silver and a dark backing material.

    I've got nothing against sodium thiosulfate :smile: In fact, we are good friends and have spent many a long night in the dark togeather :tongue:
     
  25. Barry S

    Barry S Member

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    Yes. I should add the remediation of the used KCN solution with hydrogen peroxide before disposal and/or disposal as hazardous waste. I'm not sure the low residual concentration of KCN on gloves or in wash water warrants disposal as hazardous waste, but that's an option.

    There are very fine wet plate artists using hypo or ammonium thiosulfate as fixers with superb results. However, the wet plate process is a delicate balance of materials and processes--and I achieve superior tonality using KCN. KCN also has a very high fixing capacity at a low concentration (1% compared to 20% for hypo) and washes out quickly.

    It's likely that KCN will no longer be generally available to US photographers within 12 months. Chemsavers will discontinue distribution once their current stock runs out and at this point, I don't know of any other distributor that will sell to individuals.
     
  26. alexhill

    alexhill Member

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    I had read that on an MSDS sheet. But wasn't sure exactly what that entailed. Good to know. I'm hoping I can stop by a chemical dealer in person and use my good charms on them. I also have some contacts at the university level that might be willing to act as an intermediary. I would prefer to have a chemistry dealer willing to sell to me. Makes getting uranium nitrate easier :wink: