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:
     
  6. NedL

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    Sorry to resurrect this old thread, but I rely on PE an Gerald Koch to keep me from blowing myself up or gassing myself.
    Not being a chemist, it's better to ask if something is safe or not ahead of time.

    I'm planning to make a print with ammonio-nitrate of silver brushed onto salted paper. After looking for quite a while and only finding lemon scented ammonia or plain ammonia that was cloudy, I finally found some ammonia that is nice and clear. Here is an excerpt from the instructions I'd like to follow:

    My plan is: in a small vial, I will put about 2ml of 8% silver nitrate solution. I'll add the ammonia drop by drop until the solution clears. Then I will immediately brush it onto the paper.

    Am I going to blow myself up by making silver fulminate or silver nitride or something like blasting caps?
     
  7. Photo Engineer

    Photo Engineer Subscriber

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    Just keep things from crystallizing and stay away from alcohol. Add no alcohol to the mix.

    The 28% ammonia you need is available from the Photographers Formulary. It must be kept cool.

    It can swell plastic bottles and burst some glass bottles. It can also loose strength.

    PE
     
  8. NedL

    NedL Subscriber

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    Thank you very much PE!
     
  9. NedL

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    I decided to first see if I could make household ammonia work. The strong ammonia sounds a bit nasty, and I'd have to store it safely.

    First experiment:
    I put 2 drops of 24% AgNO3 in a paper cup.
    Adding ammonia drop by drop, a brown precipitate formed after the first drop, and then it redissolved after 7 drops. That was encouraging!

    So... to make a print and needing about 50 drops total to cover my salted paper, I decided to try 12 drops of AgNO3 expecting it to take about 42 drops of ammonia. Interestingly... the brown precipitate did not form at first, but formed as I added more drops of ammonia -- it was visible after about 5 or 6 drops were added, and then increased a little before starting to redissolve. After 38 drops were added it was redissolved. It was only a little later that I realized I'd ended up right at my target of 50 drops.

    This is only 1/2 as much AgNO3 as I would normally use on a print this size, but it worked well and printed easily. Also, since the water evaporates, it could be double coated to end up with more silver... something to think about later. The result was very interesting and different from a normal salt print in a several ways... I see some potential and think it is worth exploring more.
     
  10. nmp

    nmp Member

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    NedL:

    If I understand correctly, you are using the conventional sodium chloride salted paper to coat with this ammnio-nitrate of silver. I was wondering - what would be the advantage of using this as opposed to the straight silver nitrate? I'd appreciate if you would elaborate further.
     
  11. NedL

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    Hi nmp, Yes, you are correct, I am using the ammonio-nitrate of silver brushed onto salted paper, in place of straight silver nitrate or silver nitrate mixed with a little citric acid. In the early days of salt printing, this was a common approach and it is mentioned in many early instructions for printing. Reading this description of Thomas Rodger's printing process, is what piqued my interest, both because of the ammonio-nitrate of silver and because of the use of gold chloride in the salting solution, which sounds interesting. So it's interesting just from history and a connection to the past, but honestly that's not the reason I wanted to try it.

    In salt printing it seems like every little detail makes a difference in how the final print looks. Whether it's the paper or the salt or the sizing or the toner or the light used to expose the print. So mostly I'm just curious to know what happens and how it looks. Whether there is any advantage or not, I don't know, but I expect the results to be different in some way, and can then decide if it's something I like and want to use or not.

    I've only made the one print so far, but here's what I noticed: it printed faster ( than straight silver nitrate ), and there appeared to be some fog and uneven areas on the print before processing. It was a pinker/redder color, and it seemed to have less detail in the darker areas. When I put it in gold borax toner, it did not seem to respond much... I left it in longer than I normally would and did not observe much change. But then, in the fixer, it was as though a veil was removed, and the fog and uneven areas disappeared, as well as the reddish color, leaving the highlights clean and more detail in the dark areas. The print then had a very neutral grey color just like any print that has been left in the toner for a long time. I was quite surprised to see it change so much in the hypo... usually there is little change after toning. So there were fewer visual clues about how the print was going, and it would take some practice to get used to how much to print out and how to tone it. My print was too weak, and I think if I'm going to keep trying with the weak household ammonia, it will need to be double coated and printed deeper than I'm used to ( to account for the "fading" in the fixer, and probably make toning more effective ). But at the very end, there were nice subtle pinkish hints to the colors, and I think it might have promise for a print with delicate looking tones. So the end result does look different from a salt print made with straight silver nitrate, and it will need more tries to see if it's something I like well enough to keep doing it.

    So, is there an advantage? I don't know yet, but it does make a print that looks different, and it seems to me promising enough to play around with it a little more to find out what it can do. :smile:

    Cheers,
    Ned
     
    Last edited: Oct 11, 2016
  12. nmp

    nmp Member

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    Thanks, Ned for the thorough background. I am currently gathering up materials, both chemical and the reading kinds, to make a foray in to the world of salt printing. The fact that a little detail can make a big difference, both excites and scares me. I will probably start with the basic formula. I had not come across this particular method or probably I was glossing over if I did.

    That got me thinking, apparently silver chloride has finite solubility in aqueous ammonia. It would be interesting to see what happens if you drop some NaCl solution in the concoction. Would the ensuing AgCl precipitate as it would in the case of a silver nitrate solution or would it get solubilized in presence of excess ammonia. If latter, then you would have a single part sensitizer rather than the conventional two part one. Considering of course nothing untoward happens when you mix all these together....

    Good fun!

    :Niranjan.
     
    Last edited: Oct 12, 2016