Ammonium Hypo from Sodium Hypo and Ammonium Chloride

athbr · Jun 13, 2019

I'm trying to mix up some of PE's superfix and sadly no longer can source ammonium hypo.

If I understand correctly mixing Sodium Hypo and Ammonium Chloride in solution in the following proportions should give me the 200ml of 60% ammonium hypo (plus a bit of salt):

128g of Sodium Hypo
87g of Ammonium Chloride
200ml of Water

Below are the balanced equations I used to arrive at this (bear with my HS chemistry).

Does this work? Or am I making a baseless assumption that all the hypo and chloride will react with each other?

Any tips on how to get the most out of this or is this just a plain dumb idea?

------------------------------------------------------Equation----------------------------------------------------------

1. Na2S_2O_3 + 2 NH_4Cl ⟶ (NH_4)_2S_2O_3 + 2 NaCl
2. 158g/mol + 2.53.49g/mol ⟶ 148.2g/mol + 2.58.44g/mol
3. 158g/mol + 106.98g/mol ⟶ 148.2g/mol + 116.88g/mol

This leads to a ratio of 1:1.066:0.721 Amm. Hypo : Sodium Hypo : Amm. Chloride.

So for 120g of Amm. Hypo we get: 120:127.92:86.52 which is roughly 120:128:87

Rudeofus · Jun 13, 2019

What this gives you is a mix of Ammonium Chloride and Sodium Thiosulfate, or Sodium Chloride and Ammonium Thiosulfate. Unless you have a magical way to get the Sodium Chloride out (I don't), the result will be quite a bit slower than pure Ammonium Thiosulfate. In my tests the optimum amount of Ammonium Chloride to be added to 200 g/l Sodium Thiosulfate crystalline was around 45 g/l, with a rather flat optimum between 40 and 50 g/l. That optimum amount would be lower if you used more Sodium Thiosulfate, but the resulting fixer would still be faster. Also: do you have a decent source for Ammonium Thiocyanate? You aren't going to use Potassium Thiocyanate, do you?

athbr · Jun 13, 2019

I do have a source of ammonium thiocyanate gladly.

Why is it necessary to remove the sodium chloride? Does it impede the reaction?

For some reason I believe the darkroom cookbook advised on this method. I can't seem to find it though. Perhaps I just imagined it.

koraks · Jun 13, 2019

athbr said:
Why is it necessary to remove the sodium chloride? Does it impede the reaction?

Slows it down.

RPC · Jun 13, 2019

There are some formulas that use these these two that may be of interest.

Here is link to a thread that discusses the subject, but I'm sure there are plenty of others.
https://www.photrio.com/forum/threads/rapid-fixer-without-ammonium-thiosulfate.102211/

Some of these formulas are pretty fast, but I was disappointed to find out they can't be used for color, but I don't remember why.

Rudeofus · Jun 13, 2019

@RPC : Now that you mention this thread: for reasons still not known to me, user @Relayer was able to use a lot more Ammonium Chloride than I could use with positive effect. I wonder whether impurities were the reason for this, and it may be worth while testing with your own set of chemicals.

@athbr : The best compound (in terms of speedup) for adding Ammonium ions to Sodium Thiosulfate that I have found so far was Ammonium Acetate. This one should also be quite easy to get, because one can mix it from white vinegar and Ammonia solution.

athbr · Jun 13, 2019

Rudeofus said:
@athbr : The best compound (in terms of speedup) for adding Ammonium ions to Sodium Thiosulfate that I have found so far was Ammonium Acetate. This one should also be quite easy to get, because one can mix it from white vinegar and Ammonia solution.

Rudeofus, any chance you have some more precise information on mixing this up? Say how much vinegar to ammonia solution and then how much of the ammonia acetate solution to sodium hypo?

Also, when you say "was able to use a lot more Ammonium Chloride than I could use with positive effect" how do you come to this determination? How does one figure out how much ammonium chloride (or acetate) they can add before it stops being useful.

And one final question if I can test your patience: will a hack like this ever work for colour fixer or am I doomed to importing ammonium hypo from suvatlar (somewhat expensive for me unfortunately)?

Rudeofus · Jun 13, 2019

athbr said:
Rudeofus, any chance you have some more precise information on mixing this up? Say how much vinegar to ammonia solution and then how much of the ammonia acetate solution to sodium hypo?

When I did those experiments, I worked with Acetic Acid 80% and Ammonia 24% solution. For whatever reason, when I mixed these two in 1:1 volume ratio I had close to molar balance. Here is one formula, which clears Tri-X in <50 seconds, comparable to standard rapid fixer:
Start with 600 ml/l tap water, then add:
200 g/l Sodium Thiosulfate crystalline (Na2S2O3 * 5 H2O)
20 g/l Sodium Metabisulfite (Na2S2O5)
60 ml/l Acetic Acid 80%
65 ml/l Ammonia 24% solution

Note: mixing Ammonia 24% into Acetic Acid 80% produces a lot of heat. Since dissolution of Sodium Thiosulfate cools down the water a lot, don't wait for it to fully dissolve, but use the former reaction to maintain solution temperature. Please don't do this if you are inexperienced or poorly equipped for this. Try it with a 50ml batch in a big beaker first before doing this in larger quantities.

athbr said:
Also, when you say "was able to use a lot more Ammonium Chloride than I could use with positive effect" how do you come to this determination? How does one figure out how much ammonium chloride (or acetate) they can add before it stops being useful.

Since Ammonia is a strong alkali and Hydrochloric Acid a strong acid, you can add any amount of Ammonium Chloride to an existing mix without much affecting its pH around neutral. Start with a solution consisting of 200 g/l Sodium Thiosulfate crystalline and 10-20 g/l Sodium Sulfite/Sodium Metabisulfite, set pH to around 6-7 with Ammonia, then do clip clearing tests with increasing amounts of Ammonium Chloride. You can use the same batch for consecutive tests, no need to mix fresh each time. Add Ammonium Chloride in 10 g/l increments and record clip clearing times. You will see an optimum at some amount between 40 and 100 g/l, and that's what you should then use with your specific chem supply situation.

athbr said:
And one final question if I can test your patience: will a hack like this ever work for colour fixer or am I doomed to importing ammonium hypo from suvatlar (somewhat expensive for me unfortunately)?

When it comes to counter cations of Thiosulfate, there are two effects happening:

Diffusion is faster, the smaller the cation is. Since we have to account for hydrated cations, we have the size/speed series NH4+ >> K+ > Na+ > Li+. Yes, in hydrated form K+ is smaller and diffuses faster than Na+!
There are very poorly soluble mixed salts between Na+/K+, Ag+, S2O3-- and halides. These poorly soluble salts will form, if enough silver halide has been dissolved. In terms of proneness to form these salts the speed series goes K+ > Na+ > NH4+, meaning Potassium ion will most likely form such salts at lower silver halide load, followed by Sodium ion. Needless to say, that these insoluble salts can bring fixing to a screeching halt.

When it comes to fixing color films, you have two effects favoring Ammonium Thiosulfate: faster diffusion means higher fixing speed, and reduced proneness to form these dreaded insoluble salts at high silver halide loads. With a fixer made from Sodium Thiosulfate and Ammonium Chloride/Sulfate/Acetate you get the faster diffusion speed of NH4+, but the dreaded silver salt formation from Na+.

To make a long story short: yes, Sodium Thiosulfate plus Ammonium Chloride/Sulfate/Acetate will work for color, too, but watch out for reduced capacity compared to Ammonium Thiosulfate based fixers. Expect capacity loss of 50-66% with high iodide color film. There's a good chance, especially if you can source Sodium Thiosulfate locally, that Sodium Thiosulfate plus Ammonium Chloride/Sulfate/Acetate type fixer will still be cheaper overall for you, even with its reduced capacity.

Photo Engineer · Jun 13, 2019

Rudi, Ammonia is classed as a weak alkali, but it does work out in the end. However, a dangerous amount of heat can be released in the addition of acid to base. I do not recommend it to anyone without experience.

If you insist of doing it, wear rubber gloves, a rubber apron and eye goggles. A facemask would be better.

PE

RPC · Jun 13, 2019

Rudeofus said:
When it comes to fixing color films, you have two effects favoring Ammonium Thiosulfate: faster diffusion means higher fixing speed, and reduced proneness to form these dreaded insoluble salts at high silver halide loads. With a fixer made from Sodium Thiosulfate and Ammonium Chloride/Sulfate/Acetate you get the faster diffusion speed of NH4+, but the dreaded silver salt formation from Na+.

To make a long story short: yes, Sodium Thiosulfate plus Ammonium Chloride/Sulfate/Acetate will work for color, too, but watch out for reduced capacity compared to Ammonium Thiosulfate based fixers. Expect capacity loss of 50-66% with high iodide color film. There's a good chance, especially if you can source Sodium Thiosulfate locally, that Sodium Thiosulfate plus Ammonium Chloride/Sulfate/Acetate type fixer will still be cheaper overall for you, even with its reduced capacity.

Thanks for that.

athbr · Jun 13, 2019

Photo Engineer said:
Rudi, Ammonia is classed as a weak alkali, but it does work out in the end. However, a dangerous amount of heat can be released in the addition of acid to base. I do not recommend it to anyone without experience.

If you insist of doing it, wear rubber gloves, a rubber apron and eye goggles. A facemask would be better.

PE

Honestly I am enough of a klutz to be dissuaded by this.

Here's what I'll try so as not to get my face exploded:

1. Mix Superfix with Sodium Hypo
2. Add small amount of Ammonium Chloride/Sulfate
3. Clip Test
4. Repeat until results don't get any better
5. Add acetic acid until Ph is ~6.5

If the fix and wash times for BW are reasonable I can live with it. I'll test it for colour but considering I do much less colour work, I can probably stomach the expense for true ammonium hypo for that use case.

Thanks for the immense help. Would be lost without this knowledge.

mshchem · Jun 13, 2019

athbr said:
I'm trying to mix up some of PE's superfix and sadly no longer can source ammonium hypo.

If I understand correctly mixing Sodium Hypo and Ammonium Chloride in solution in the following proportions should give me the 200ml of 60% ammonium hypo (plus a bit of salt):

128g of Sodium Hypo
87g of Ammonium Chloride
200ml of Water

Below are the balanced equations I used to arrive at this (bear with my HS chemistry).

Does this work? Or am I making a baseless assumption that all the hypo and chloride will react with each other?

Any tips on how to get the most out of this or is this just a plain dumb idea?

------------------------------------------------------Equation----------------------------------------------------------

1. Na2S_2O_3 + 2 NH_4Cl ⟶ (NH_4)_2S_2O_3 + 2 NaCl
2. 158g/mol + 2.53.49g/mol ⟶ 148.2g/mol + 2.58.44g/mol
3. 158g/mol + 106.98g/mol ⟶ 148.2g/mol + 116.88g/mol

This leads to a ratio of 1:1.066:0.721 Amm. Hypo : Sodium Hypo : Amm. Chloride.

So for 120g of Amm. Hypo we get: 120:127.92:86.52 which is roughly 120:128:87

Old Agfa formula #304
Water 750ml 52°C
Na Thiosulfate 200 grams
NH4+ chloride 50 grams
Potassium metabisulfate 20 grams
Water t make 1 liter
Use undiluted. Film 3 X clearing time, Paper 3 to 5 minutes.

Photo Engineer · Jun 13, 2019

Do not use any chemical with the word "SULFATE" in it in a fix. It slows down fixing and washing.

This is a general rule.

PE

athbr · Jun 13, 2019

Photo Engineer said:
Do not use any chemical with the word "SULFATE" in it in a fix. It slows down fixing and washing.

This is a general rule.

PE

Thanks PE will keep this in mind.

athbr · Jun 13, 2019

athbr said:
Thanks PE will keep this in mind.

Wait, isn't hypo thioSULFATE?

athbr · Jun 13, 2019

Also,

On another note. Iv'e read that sodium sulfate is rather insoluble in low temperatures:
source:http://caffenolcolor.blogspot.com/2012/05/another-way-to-produce-fixer.html

Could you say:
1. Mix Sodium Hypo and Ammonium Sulfate until clip tests start to slow
2. Put the mixture in the fridge
3. Next day filter out collected sodium sulfate.
4. Start again on step 1.

mshchem · Jun 14, 2019

So, is Kodak and/or Ilford Rapid Fixer, Hypam not available in Brazil? The best Churrasco on Earth and the Caipirinha, (watch out for this!) better enjoy the local beer.
There's got to be ammonium thiosulfate solution or Rapid Fixer available. I know that the prices are higher, that's definitely an issue.

We can buy Ilford and Tetenal products for less in the USA than in the EU. And it's not just the taxes .

mshchem · Jun 14, 2019

Availability
Ammnoium thiosulfate is sold as fertilizer, as aqueous solution. THIO-S is one such product. It contains 30-60% ammonium thiosulfate by mass. To obtain the pure compound, gently heat the solution for several hours at ~90 °C, then cool the concentrated solution to crystallize the compound.

Ammonium thiosulfate is also available as photographic fixer.

Preparation
Ammonium thiosulfate can be produced by mixing two solutions of ammonium sulfate and sodium thiosulfate, followed by cooling, filtration of the sodium sulfate. The filtrate is concentrated and cooled to recrystallize the compound.

Rudeofus · Jun 14, 2019

@mshchem : Even at a low temperature there can be up at 50 g/l Sodium Sulfate left in this liquid you prepared. Not sure whether such a product would be useful as fixer. The reason PE commented on sulfate is the Agfa 304 formula you incorrectly posted with metabisulfate instead of metabisulfite.

mshchem · Jun 14, 2019

Rudeofus said:
@mshchem : Even at a low temperature there can be up at 50 g/l Sodium Sulfate left in this liquid you prepared. Not sure whether such a product would be useful as fixer. The reason PE commented on sulfate is the Agfa 304 formula you incorrectly posted with metabisulfate instead of metabisulfite.

I poked the wrong key. I use Kodak and Ilford Rapid fixers.

Photo Engineer · Jun 14, 2019

athbr said:
Wait, isn't hypo thioSULFATE?

Sorry, that is the one exception.

PE

athbr · Jun 14, 2019

Rudeofus said:
@mshchem : Even at a low temperature there can be up at 50 g/l Sodium Sulfate left in this liquid you prepared. Not sure whether such a product would be useful as fixer. The reason PE commented on sulfate is the Agfa 304 formula you incorrectly posted with metabisulfate instead of metabisulfite.

Great point.

Thas said, looking at the "Rapid Fixer without ammonium hypo" forum you posted, Relayer was able to get 43 seconds from a solution with ammonium sulphate vs 35 from ammonium chloride. And that's without trying to filter out the sulphate.

I wonder if one did they might bring that a bit lower? Maybe even lower than the ammonium chloride solution? I'll definitely try it out and see what results I get. Ammonium sulphate is cheap enough around me to give it a go.

Either way, I know all of this is just second tier to pure ammonium hypo. But if I can figure out something that works significantly faster than sodium hypo I am happy.

athbr · Jun 14, 2019

mshchem said:
So, is Kodak and/or Ilford Rapid Fixer, Hypam not available in Brazil? The best Churrasco on Earth and the Caipirinha, (watch out for this!) better enjoy the local beer.
There's got to be ammonium thiosulfate solution or Rapid Fixer available. I know that the prices are higher, that's definitely an issue.

We can buy Ilford and Tetenal products for less in the USA than in the EU. And it's not just the taxes .

It's definitely expensive when you account for:

- high cost of international shipping
- high cost of domestic shipping
- very high import duties
- very high sales tax

Works out to about U$35 for rapid fixer. About U$15 for a roll of HP5. This is also a conservative comparison considering the exchange rate between Reais and Dollars is roughly 4:1 now whereas historically it has been 2:1. At 2014 prices and exchange rates it was roughly U$50 for fixer and U$20 for a roll of HP5.

Scratch mixing has definitely come about as a way to (significantly) lower dev costs. Incidentally, it was searching for formulas that got me to APUG in the first place.

I definitely have stuff here already to do Sodium Hypo from scratch very cheaply. So it's not like one is without options. That said, anything that can make the process faster and less wasteful with water and that doesn't cost an arm and a leg to execute is worth an experiment in my eyes.

Photo Engineer · Jun 14, 2019

athbr said:
Great point.

Thas said, looking at the "Rapid Fixer without ammonium hypo" forum you posted, Relayer was able to get 43 seconds from a solution with ammonium sulphate vs 35 from ammonium chloride. And that's without trying to filter out the sulphate.

I wonder if one did they might bring that a bit lower? Maybe even lower than the ammonium chloride solution? I'll definitely try it out and see what results I get. Ammonium sulphate is cheap enough around me to give it a go.

Either way, I know all of this is just second tier to pure ammonium hypo. But if I can figure out something that works significantly faster than sodium hypo I am happy.

Look at that table above and try to rethink your ideas about the times. There are some pretty bad results in the right hand of the table.

PE

athbr · Jun 14, 2019

Photo Engineer said:
Look at that table above and try to rethink your ideas about the times. There are some pretty bad results in the right hand of the table.

PE

Sure but wouldn't they get better if one could remove the ammonium sulfate?

edit: It is also much cheaper than ammonium chloride. So if it worked ok that would be kinda cool.

Ammonium Hypo from Sodium Hypo and Ammonium Chloride

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