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  1. #1

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    substitute for nitric acid?

    Is there a substitute for nitric acid?

    I've used sodium bisulfate as a substitute for sulfuric acid; I'm looking for something similar.

    I use 15ml of nitric acid in a litre of bleach for the B3 bleach in the Dupont Varigam toner system. I would love to have a powder I could mix in as I'm not all that comfortable with strong acids.

    thank you!
    Last edited by Marco Buonocore; 02-16-2012 at 07:05 PM. Click to view previous post history.

  2. #2
    keithwms's Avatar
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    What's the purpose of the nitric in this formula? Can you post the whole formula? If we know what it's meant to do we can probably suggest a substitute. If it's just to oxidize something then...

    For safety, what most of us do, who work with acids, is make a much weaker "x" molar solution and work with that.
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  3. #3

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    Keith,

    It's a bleach from the Defender / Dupont varigam toner system. . they are thiocarbamide sepia Toners.

    the formula:

    bleach B3

    to make 1l
    22g potassium ferricyanide
    35g sodium chloride
    15ml nitric sciences

  4. #4

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    I always found concentrated nitric was very good for burning off warts. You have to be careful though! Use a glass straw, very small droplets, avoid breathing the fumes while it dries and if the underlying skin gets very red and sore, stop using the nitric for a few days. Just sayin'
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  5. #5
    keithwms's Avatar
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    Well, okay, 15mL of nitric in 1 L of water is what, a ~200 mM solution? So you just make up a big bottle of that, which will be safer to work with, then you don't have to work with the concentrated stuff anymore.

    You can check the math...

    http://www.lgpnet.com/science/molarity.htm
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  6. #6

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    If you get the nitric acid on your skin, it'll turn it a shade of highlighter yellow. My college chemistry prof called this "dinitroskin." Apparently the nitric acid reacts with an amino acid in your skin and produces a yellow dye. If it's left on long enough, the top layer becomes less skin-like and more paper-like.

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  7. #7

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    Regarding the yellow: I wonder if there's not a similar amino acid in the gelatin in photo paper, because prints bleached in the B3 bath go very much that highlighter colour. Must brighter and more difficult to wash off than just plain ferricyanide.

    Keith: Thank you for the advice, that website will do the trick nicely!

  8. #8
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    From looking at it, this is just a rehalogenating bleach. I've seen plenty of recipes out there. It might be worthwhile to try one of these and see what happens.
    Trying to be the best of whatever I am, even if what I am is no good.

  9. #9
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    Quote Originally Posted by keithwms View Post
    Well, okay, 15mL of nitric in 1 L of water is what, a ~200 mM solution? So you just make up a big bottle of that, which will be safer to work with, then you don't have to work with the concentrated stuff anymore.

    You can check the math...

    http://www.lgpnet.com/science/molarity.htm
    In regards to dilution, do not add concentrated acid to potassium ferricyanide solution, unless you enjoy breathing hydrogen cyanide gas.

    Quote Originally Posted by Marco Buonocore View Post
    Keith,

    It's a bleach from the Defender / Dupont varigam toner system. . they are thiocarbamide sepia Toners.

    the formula:

    bleach B3

    to make 1l
    22g potassium ferricyanide
    35g sodium chloride
    15ml nitric sciences

    nitric sciences??
    Last edited by Athiril; 02-18-2012 at 04:34 AM. Click to view previous post history.

  10. #10
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    I would think that that bleach would cause loss of highlight detail, due to the formation of AgCl and then the reverse reaction with the formation of AgNO3. This type of rehal bleach was abandoned due to that type of problem.

    Just a thought for you all. It is a possibility due to the kinetics of the reaction.

    PE

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