Ammonium chloride in salt prints

Discussion in 'Alternative Processes' started by Jerevan, Aug 26, 2006.

  1. Jerevan

    Jerevan Subscriber

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    Sorry about this, but I seem to have to much spare time on my hands... :smile:

    A standard salt print; it's first a sodium chloride (NaCl) solution and then sensitizing with a silver nitrate solution. But, I have seen in several instances that ammonium chloride (NH4Cl) is used for the salting (giving a more red-brown tone and a slightly higher print speed, the sources say).

    The MSDS says it's a no-no to get ammonium chloride near nitrates. Is any (violent or dangerous) reaction inhibited as the ammonium chloride is in a solution going into the paper/sizing? (At first I was thinking the reaction between the ammonium chloride and silver nitrate could become fulminating silver but that doesn't seem to be the case.)
     
  2. Ole

    Ole Moderator Staff Member Moderator

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    With the concentrations used in "paper salting", it's perfectly safe. The silver nitrate is the most "dangerous" compound; the resulting silver chloride and ammonium nitrates are "safer".

    I think it must be the ammonium nitrate that's the "no-no", it's an important part of the most used commercial explosive.
     
  3. juan

    juan Subscriber

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    A photography professor here has been making salt prints with ammonium chloride for 25-years with no ill effects. Following his recommendation, I've begun to use it, too. No explosions or poison gas yet.
    juan
     
  4. Photo Engineer

    Photo Engineer Subscriber

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    If you use ammonia to 'digest' the silver halide when making emulsions, the leftover is ammonium nitrate. In solution it is not harmful.

    The solid powder is a powerful explosive or ingredient in explosives as are many nitrates. Gunpowder contains sodium nitrate.

    Many years ago, a ship in a harbor in the US blew up when carrying ammonium nitrate and the cargo got too hot.

    So, just be careful with overheating large quantities of the dry solid, especially in a closed container. The amount you have on a paper sheet would probably just fizzle if you burned it.

    Be aware that you can also form silver fulminates when ammonia is present with silver. This was once used in blasting caps.

    PE
     
  5. Jerevan

    Jerevan Subscriber

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    Okay, thank you very much for your answers - I'll post a photo of my results as soon as I get any - still wating for paper and chemcials. :smile: