Silver Nitrate and Tincture of Iodine?

Discussion in 'Alternative Processes' started by Swellastic, Jan 15, 2013.

  1. Swellastic

    Swellastic Member

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    Hello everyone. Having read a bit about the daguerreotype process recently, I started thinking about how it would be possible to translate the mechanics of the process into something similar that one could use, say, on paper. Since fumes of elemental iodine form silver iodide on a silver surface, would the same happen (the formation for silver iodide) if one were to brush a solution of silver nitrate on a piece of paper and then afterwards brush on some tincture of iodine? What would happen chemically, if anything? I just started thinking about it and figured I might ask the bright minds that seem to mingle on the forums here.
     
  2. Gerald C Koch

    Gerald C Koch Member

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    What you propose is essentially the same as salted paper using iodine in place of sodium chloride. The paper would have to be developed using a conventional developer to produce a negative image. There would be little similarity to what you propose and the Daguerreotype process which forms a positive image created by mercury vapor.

    A Daguerreotype image is composed of silver which has a rougher surface than the surrounding silver. The rough surface scatters the light and so appears darker than the surrounding bright silver.
     
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  3. Swellastic

    Swellastic Member

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    Thank you very much for your answer, Mr. Koch - I thought that would be the case. I do know that what i propose shows little similarity with the Daguerreotype process. The only similarity would be the reaction of silver and iodine to form silver iodide. But I nonetheless thank you for elaborating further
     
  4. Gerald C Koch

    Gerald C Koch Member

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    In itself salted paper can be quite a bit of fun. You can do just positives or extend it to paper negatives. The only chamicals you need are silver nitrate and table salt.
     
  5. cliveh

    cliveh Subscriber

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    You have touched on a beautiful subject that is the exploration of halogen compounds at the dawn of photography. I would suggest you read Talbot’s Note Books P & Q and use this as a basis for experimentation. You will not be disappointed in what your practical experiments reveal.
     
  6. doughowk

    doughowk Subscriber

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    Mentioning tincture of iodine reminded me of some comments in Barry Thorton's "Elements" about using it as a local bleach rather than pot. ferricyanide. Unfortunately, the book is without index. Hopefully not mis-directing this thread; but am curious about the chemical process involved.
     
  7. Gerald C Koch

    Gerald C Koch Member

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    Iodine converts mettalic silver into silver iodide. The silver iodide can then be removed by fixing. The silver is oxidized to Ag+ and the iodine is reduced to I-. The overall equation is

    2Ag + I2 --> 2AgI
     
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