Ammonium Thiosulfate

clayne · Oct 25, 2010

Why is this not commonly available in powder form? It seems everyone sells it in solution only. I'm interested because of the economy of powder for shipping, etc.

I've also heard mention of short shelf life. Does it's life actually go up in solution?

Athiril · Oct 25, 2010

AFAIK, it is only sold in 60% solution.

A chemist should correct me if I'm wrong, get your hands on some Sulphur (cheap and in supermarkets) and Ammonium Sulphite, and you can probably follow the same reaction as Sulphur + Sodium Sulphite if you really want it.

If you cant get Ammonium Sulphite, you can follow this method http://www.youtube.com/watch?v=okvvD3-DF9U but put the gas from metabisulphite through a solution of ammonia instead.

All a bit of a long method to get it... you could just buy something like Ilford Rapid Fixer if you cant find any/shipping becomes a problem.

clayne · Oct 25, 2010

What I've heard is combining Ammonium Chloride and readily available Sodium Thiosulfate to arrive at something similar. Can any of the chemists in the house tell me if this is equivalent? Looking over Oly's fixer formula it seems like a good mix.

Athiril, well it's very available here, I just want to stop the ordering of things that continually just include water unless it's absolutely necessary (e.g. Selenium). I have ready access to water, it's the powder that I'd prefer in cases where they aren't reasonably dangerous.

Vlad Soare · Oct 25, 2010

The guy I use to buy chemicals from sells ammonium thiosulfate in dry form. Here is a selection of the chemicals he sells. It's in German, but many chemical names are not far from their English counterparts. Ammonium thiosulfate is no. 151 in dry form, and nos. 30, 31, 109 in 60% solutions.
But this guy's prices are quite high, the euro is strong, and shipping from Germany isn't cheap either. So even with the added water content, you may still be financially better off buying a 60% solution from an American dealer.

jim appleyard · Oct 25, 2010

Formulary sells it in powder form.

clayne · Oct 25, 2010

jim appleyard said:
Formulary sells it in powder form.

Where? I only see 60% solution being sold by PF.

jim appleyard · Oct 25, 2010

As soon as I got done replying to your question, I went to the PF site and sod. thio in powder form is no longer listed. Perhaps an email to PF will get you an answer; they're very good about things like that.

I DID purchase some about two years ago...

Removed Account2 · Oct 25, 2010

You can get sulphur and ammonium sulphite in a supermarket? Man that is a big difference from Europe!

clayne · Oct 25, 2010

Erik Prestmo said:
You can get sulphur and ammonium sulphite in a supermarket? Man that is a big difference from Europe!

Yep. In fact you can just roll up to a gas station and ask the attendant "Hey Chief, throw me a pack of Alum Sulfite" and you're set to go.

Of course not, my friend.

You can't buy any of this stuff in the supermarket at photographic grade at least. Additionally it's seeming difficult to even find it from typical photographic outlets - most likely due to the fact that people just buy the liquid form.

Granted, 60% isn't that bad, weight-wise.

Athiril · Oct 25, 2010

Erik Prestmo said:
You can get sulphur and ammonium sulphite in a supermarket? Man that is a big difference from Europe!

Sulphur yes, Not Ammonium Sulphite (but you can get sodium metabisulphite and ammonia at the supermarket)

Photo Engineer · Oct 25, 2010

Ammonium Thiosulfate is quite difficult to make in powder form, is less stable and usually is more expensive. The liquid form keeps just about forever though. I have some 5+ years old that is still just fine. The Formulary had both forms, but usually just stocks the solution form due to its excellent keeping properties and its cost.

PE

georgegrosu · Oct 25, 2010

Ammonium thiosulphate solution has a concentration of 58-60% and has a density of 1.679 g / mL.
One liter of 60% solution of ammonium thiosulfate weighs about 1.7 kg and I make 5.5 liters of fixer.
From a kg of sodium thiosulfate I make about 4-5 liters of fixer.
I use ammonium thiosulphate for b&w and color fixer.
George

Gerald C Koch · Oct 26, 2010

One problem with anhydrous ammonium thiosulfate is the it will absorb moisture from the air and set into something only slightly less durable than concrete.

Since the liquid form is only 40% water you are not really paying that much extra for shipping.

Before ammonium thiosulfate was readily available rapid fixers were made by adding an ammonium salt such as ammonium chloride or ammonium sulfate to the fixer. There are several formulas available on the net.

Agfa 304 Kodak F-8
for papers for films

Water (50 C) 600 ml 750 ml
Sodium thiosulfate pentahydrate 200 g 360 g
Ammonium chloride 50 g 50 g
Potassium metabifulfite 20 g - - -

Dissolve the thiosulfate in the water and allow to come to room temperature. Dissolve the remaining ingredients in a small amount of water and add with rapid stirring to the thiosulfate solution. Then make up the solution to 1 l.

Use full strength. Most films will clear in 3 - 5 minutes.

Ian Grant · Oct 26, 2010

clayne said:
What I've heard is combining Ammonium Chloride and readily available Sodium Thiosulfate to arrive at something similar. Can any of the chemists in the house tell me if this is equivalent? Looking over Oly's fixer formula it seems like a good mix.

Athiril, well it's very available here, I just want to stop the ordering of things that continually just include water unless it's absolutely necessary (e.g. Selenium). I have ready access to water, it's the powder that I'd prefer in cases where they aren't reasonably dangerous.

You can form Ammonium Thiosulphate using Ammonium Chloride and Sodium Thiosulphate but the resulting fixer has less capacity than using Ammonium Thiosuplhate itself due to the prescence of the Sodium Chloride formed.

You can always buy the Ammonium Thiosulphate in crystal form the store it as a solution. The major problem is once it start to absorb water you an't weigh it accurately. It keeps ok in a full airtight container.

Ian

nworth · Oct 26, 2010

clayne said:
Why is this not commonly available in powder form? It seems everyone sells it in solution only. I'm interested because of the economy of powder for shipping, etc.

I've also heard mention of short shelf life. Does it's life actually go up in solution?

The reason you see ammonium thiosulfate only as a solution is that the solid is hygroscopic - it absorbs water from the air. In a climate that is at all humid, you have no idea of how much of the compound is in the powder you measure out, since the absorption from the air makes the hydration uncertain. The powder is easily made, and it is available, but it is almost never seen for photographic use.

RalphLambrecht · May 29, 2011

jim appleyard said:
Formulary sells it in powder form.

I cannot find it on their website anymore. Looking myself for ammonium thiosulfate in crystalline form.

Ian Grant · May 30, 2011

Silverprint in London stock Ammonium Thiosulphate in crystal form. It should be quite easy to get locally as well it's worth asking your local pharmacist (dispensing chemists) as they can often get chemicals easily.

Ian

Vlad Soare · May 30, 2011

Silverprint don't ship any chemicals outside UK.

jonw · Mar 24, 2017

Ian Grant said:
You can form Ammonium Thiosulphate using Ammonium Chloride and Sodium Thiosulphate but the resulting fixer has less capacity than using Ammonium Thiosuplhate itself due to the prescence of the Sodium Chloride formed.

You can always buy the Ammonium Thiosulphate in crystal form the store it as a solution. The major problem is once it start to absorb water you an't weigh it accurately. It keeps ok in a full airtight container.

Ian

Old thread, but if you use Ammonium chloride and Sodium Thiosulphate (Hypo), what amounts are used with how much distilled water to substitute for Ammonium Thiosulphate in making TP-3 fixer?

Gerald C Koch · Mar 25, 2017

You just can't take X amount of sodium thiosulfate plus Y amount of ammonium chloride and wind up with something equivalent to TP-3. Things are not that simple. As Ian points out the sodium chloride present in the fixer slows the fixing rate. If you look at my post #13 there is a formula for an Agfa fixing bath. This will act faster than a plain hypo bath but not as fast as an ammonium thiosulfate one. I haven't done the math but the amount of savings over an ammonium thiosulfate fixer is probably not that large. But the formula is useful if you cannot obtain ammonium thiosulfate for some reason.

jonw · Mar 25, 2017

Thank you Gerald.

Ian Grant · Mar 25, 2017

Since the thread started I've use some Agfa 304 fixer which I mixed up shortly after. While it's not quite as fast as Hypam/Ilford Rapid Fixer at 1+4 it's considerably faster than a standard Sodium Thiosulphate based fixer. It's also still working perfectly after a number of years, I've checked the clearing times and silver level.

Ian

Ian Grant · Mar 25, 2017

Gerald, Mason states that Ammonium Thiosulphate is more stable if there's 20% Sodium Thiosulphate present, so perhaps Agfa 304 is actually more stable than say Hypam or Ilford & Kodak Rapid Fixers.

Ian

Marco Buonocore · Mar 25, 2017

Ian Grant said:
Since the thread started I've use some Agfa 304 fixer which I mixed up shortly after. While it's not quite as fast as Hypam/Ilford Rapid Fixer at 1+4 it's considerably faster than a standard Sodium Thiosulphate based fixer. It's also still working perfectly after a number of years, I've checked the clearing times and silver level.

Ian

Hello Ian - Could you estimate the fixing time for double weight, fiber paper with the Agfa 304 Fixer?

Ian Grant · Mar 25, 2017

Marco Buonocore said:
Hello Ian - Could you estimate the fixing time for double weight, fiber paper with the Agfa 304 Fixer?

Around 2 minutes I would think, I looked in my 3 Agfa/Orwo Rezepte books and there's no times given, but it's recommended for Films & Plates not paper by Agfa/Orwo. The clearing time with films is quite fast less than 30 seconds, but a lot depends on throughput.

Ian

Ammonium Thiosulfate

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