Source for Sodium Selenite

Discussion in 'B&W: Film, Paper, Chemistry' started by Claire Senft, Sep 17, 2008.

  1. Claire Senft

    Claire Senft Member

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    I have in the past made Flemish toner directly from Selenium metal. My only problem is the very short shelf life of the mixed toner. Selenium metal is easily purchased and inexpensive. I am fully aware of the toxicity situation.

    Is it possible to make Sodium Selenite form Selenium metal? If so how would it be done.

    I know that it can be had as a mineral supplement in capsules but I would get very little chemical woth a great deal of additives.

    Does any one have a source for Sodium Selenite? About 15 grams would make approx. (1) gallon of a toner similar KRST.
     
  2. amuderick

    amuderick Member

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    My gut was right. See here from wikipedia:

    "The sodium selenite salt is usually prepared by the reaction of selenium dioxide with sodium hydroxide:

    SeO2 + 2 NaOH → Na2SeO3 + H2O "

    Selenium Dioxide can also be purchased as Selenous (or Selenious) acid.

    If you can get selenium metal, then you can make selenium dioxide by either burning the metal in air or reacting with hydrogen peroxide.

    Two step reaction. Be careful. Should be a fun project.
     
  3. dancqu

    dancqu Member

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    I've a small quantity of sodium selenite purchased
    from a near by chemical supply house. There are
    transport restrictions as it is most hazardous.

    I've yet to make use of it. Do you happen to know
    of a formula which makes use of it? I do know that
    the elemental form can be dissolved in sodium
    sulfite solution. Dan
     
  4. eclarke

    eclarke Member

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  5. Claire Senft

    Claire Senft Member

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    Thank you all.

    Here is a formula for a product similar to KRST.
    Water 500ml
    Ammonium Thiosulfate 50% Sol. 100ml
    Sodium Sulphide 30grams
    Sodium Selenide 4grams
    Water to make a liter.

    This formula was listed in May/June Photo Techniques magazine. It was supplied by Dr. Robert Chapman. If you are going to make this toner I advise wearing a dust mask. It is highly toxic thru inhalation and or course ingesting it is also deadly.
     
  6. eclarke

    eclarke Member

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    If you are really in Milwaukee, check with Brian in the chemicals department at Laabs Pharmacy. I've bought many exotic chemicals form him...Evan Clarke
     
  7. Claire Senft

    Claire Senft Member

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    I have purchased items from Laabs also.

    Who would lie about being in Milwaukee?
     
  8. dancqu

    dancqu Member

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    Similar to KRST? I don't see that. The results may be similar
    but that formula is far from. First it is the ide of selenium
    rather than the ite. Secondly is the inclusion of sodium
    sulfide and so much of it.

    As I recall a selenium toner may be composed of nothing
    more than some small amount of elemental selenium
    dissolved in a solution of sodium sulfite. Dan
     
  9. Photo Engineer

    Photo Engineer Subscriber

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    There is a big difference between Na2S and Na2SO3 (IDE vs ITE) and Na2Se and Na2SeO3 (IDE vs ITE). The latter two are far more toxic of course, and the IDES are far less stable and more toxic than the ITES. Beware the IDES of Selenium and March both, or you can end up like big Julie with a pain in the portico.

    These chemicals will get to you right in the rotunda! Then you lose your hair and any gender associated attributes :wink: and it goes downhill after that.

    Beware of a garlic odor on your breath. By that time it is too late usually.

    PE
     
  10. dancqu

    dancqu Member

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    Google Groups rec.photo.darkroom

    Search rec.photo.darkroom for, sodium selenite .
    There a lot of information. Some very meaty.

    IIRC Kodak up untill a few years ago made available
    a toner blend of selenium and sulfide. A Kodak formula
    was made available via the WWW for those interested.

    Some one may correct me but I believe it was Kodak that
    added the RAPID, ammonium thiosulfte, to selenium toners.
    Also I've read it implied that the thiosulfate acts to make
    selenium a safer toner.

    I wonder if Sodium thiosulfate might not work just as
    well. That have been KSST. Dan
     
  11. Photo Engineer

    Photo Engineer Subscriber

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    Dan;

    I've heard the same, but never inside EK. The interesting thing is that if it does, the means is unclear except for the following possibility...

    Just as Sodium Sulfite -> Sodium Sulfate in hypo solutions, thereby protecting hypo from oxidation, the Selenite might do the same thing and the Selenate is less toxic, but IDK by how much. And, since I don't want to work with it, I have not run, nor don't intend to run the tests. I was exposed to lots of Selenium Dioxide in grad school making alpha-diketones. After listening to stories at EK and finding their reluctance to get into Selenium sensitization and Selenium sensitizing dyes, I am a bit too negative about Se.

    PE
     
  12. eclarke

    eclarke Member

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    A Chicagoan in hiding:D...EC
     
  13. Claire Senft

    Claire Senft Member

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    I MADE A BIG MISTAKE:

    I originally asked for information on Sodium Selenite. This is what I wanted.

    THE FORMULA THAT I LISTED WAS ERRONEOUS:

    IT SHOULD READ AS FOLLOWS:

    water 500ml
    Ammonium Thiosulfate (50% sol.) 100ml
    Sodium Sufide 30grams
    Sodium Selenite 4grams
    water to make 1 liter

    I know very little about chemistry.
    Does this appear to be more like KRST than the incorrect version?
     
  14. Photo Engineer

    Photo Engineer Subscriber

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    Not to be picky, but the Sodium Sulfide has a very very strong odor of rotten eggs. Kodak toner does not IIRC. So, I doubt if this is exactly like the Kodak product. The solution described above should be alkaline which might repress the odor, but the solid would stink quite a bit.

    IDK, just a thought. I don't know the KRST formula and never did, being very disinterested in compounding selenium formulas.

    PE
     
  15. psvensson

    psvensson Member

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    Claire, KRST is a straight selenium toner. The formula you provided has sulfur as well, which makes it more like the old Kodak Polytoner. Flemish toner also combines sulfur and selenium. If that's what you're looking for, consider buying Moersch Carbon Toner from Freestyle, now that they carry it. It contains sodium selenite and sodium sulfide.
     
    Last edited by a moderator: Sep 19, 2008
  16. Trevor Crone

    Trevor Crone Member

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    The only published Kodak selenium toner formula I've come across is T-55.

    T-55 selenium toner

    Stock solution
    sodium sulphite, anhydrous - 150g
    selenium powder - 6g
    ammonium chloride - 190g
    water to make 1L

    Dissolve the sodium sulphite in 750ml of hot water. When completely dissolved add the selenium powder and boil for approx 30 minutes*. Any remaining insoluble matter must be filtered off. When cool add the ammonium chloride and stir until completely dissolved. Then make up to 1L with cold water.

    For use dilute 1:5, 1 part T-55 to 5 parts water.

    *The heating (boiling) of selenium is a very hazadous procedure and something I would certainly not recommend with out access to a fully working/tested fume cupboard. Something I once had access to when I used to prepare this solution.

    Also note that this is not the same as KRST.
     
    Last edited by a moderator: Sep 19, 2008
  17. Kirk Keyes

    Kirk Keyes Member

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    Perhaps you should think twice about making something like this. The raw constituents are not as nice and safe as most other photo chemicals.

    I think this is similar to what Kodak used to call "Polytoner" - it was a mix of selenium and sulfide toners.
     
  18. Kirk Keyes

    Kirk Keyes Member

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    A safer way to make something like this would be to take KRST and add a bit of sodium sulfide and see how that goes. It's still going to be stinky, but much less hazardous to do.
     
  19. Aurum

    Aurum Member

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    I've not experienced Selenium toner, but PE is right about the odour of selenium compounds. I've been a fan of old valve (Tube) equipment since I was young, and some of them had selenium recifiers in there.
    I tried reviving a old piece of kit that had one in that wanted to stay dead. The link attached is an indication of what happens when you don't pull the power quick enough. I was lucky and killed the power very quickly before things got anywhere near dangerous

    http://yarchive.net/electr/selenium_rectifiers.html

    It was like cleaning out the rotting bins at the Gilroy Garlic Festival. Google that if you have a strong stomach
     
  20. dancqu

    dancqu Member

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    Kodak Polytoner. That is the one I had in mind and refered
    to in my post # 10. Kodak has/had posted a formula for
    it's home brew replacement.

    Apparently the sulfur contained in older KRST prodution
    accounted for it's 'archival' effects. New, and now for
    some years, the product has been minus that sulfur.
    At least there has been no word to the contrary.

    By all accounts the addition of some little sulfur to
    off the shelf KRST SHOULD restore it's 'archival'
    nature. All interested in the old Kodak Poly
    should do a Google search. Dan