Ammonia / tri-ammonium citrate for Simple Cyanotype

Andrew O'Neill · 2025-07-22T11:25:41-0400

{Moderator edit: this thread was split off of the Ferroblend process thread: https://www.photrio.com/forum/threads/a-blended-ferrocyanide-print-process.212808 where these posts started as a follow-up on the possibility to use Simple Cyanotype, but the question is relevant in general, so it deserves its own thread}

Question for @Raghu Kuvempunagar or @koraks:
The Simple Cyanotype calls for 10% ammonia. I only have the Kroger brand, which is 1-3%. Can I still use it? What adjustments if any, would I have to make to it? Thanks!

Andrew O'Neill · 2025-07-22T11:41:25-0400

I just checked online sources for the higher grade ammonia hydroxide, and there is no way that I will pay what they are asking!

koraks · 2025-07-22T11:43:43-0400

I've never used Simple Cyanotype, so I'd have to check the documentation to see if you can substitute the 10% ammonia with 10x the volume of 1% ammonia. That would be the obvious solution.

Andrew O'Neill · 2025-07-22T11:53:38-0400

@koraks thanks! That would be the obvious solution, but only if the ammonia I have is 1%. It could be, but I'm not 100%.

koraks · 2025-07-22T12:01:00-0400

I quickly checked the formula and you cannot substitute a larger volume of 1% ammonia - or even 2% for that matter. You'd end up with a sensitizer that's at best something like 3 times less concentrated than it should be. Maybe it would still work e.g. if you double coat the paper, but it's going to be suboptimal.

The local supply situation of chemistry is notoriously variable between countries, so IDK what the situation is in Canada. But I'd be surprised if there's no way to get hold of e.g. 10% ammonia at a reasonable price. It's such a common chemical building block; there are thousands of tons of the stuff in Canada, so there's bound to be a way to get hold of a tiny amount of it. There may be regulations in effect on higher concentrations of the stuff, but I'd expect that 10% should be accessible also for private individuals. But that's just a guess.

I just checked and I can buy 25% ammonia here with ease at a cost of around €4/liter and this seems to be available to private consumers just the same. It's sold as a cleaning product. It's also commonly used as a de-greasing agent in painting.

PS: ammonia sold here in supermarkets etc. for household purposes is around 5%v/v. That should work. Maybe something similar is available where you live as well.

Andrew O'Neill · 2025-07-22T12:10:37-0400

Too expensive here. I'll put Simple Cyanotype on the shelf for now. Oh well...

Raghu Kuvempunagar · 2025-07-22T12:39:26-0400

Andrew O'Neill said:
I'll put Simple Cyanotype on the shelf for now. Oh well...

If Triammonium Citrate is available to you, it can be used in Simple Cyanotype in place of Ammonia as per @Mike Ware's recommendation:

Simple Cyanotype

Critical tests of cyanotype by John Isner, leading exponent of the Piezo Digital Negative system, have inspired me to devise a sensitizer that is much more reliable than the ‘Classic’ cyanotype and more photochemically precise than my ‘New’ version of 1995. To distinguish it from the other two...

www.photrio.com

Andrew O'Neill · 2025-07-22T12:46:03-0400

@Raghu Kuvempunagar thanks for that! I don't have any on hand, but I'll see if Jacques at Argentix does. Cheers!

Andrew O'Neill · 2025-07-22T14:51:59-0400

@Raghu Kuvempunagar I am unable to source Triammonium Citrate through Argentix... I did find it at a chemical supplier here in Canada, but they want an arm and a leg. Is there anything else that could replace Triammonium Citrate?

Andrew O'Neill · 2025-07-22T14:52:54-0400

The closest maybe would be ammonium citrate, Dibasic? What do you think?

nmp · 2025-07-22T16:36:03-0400

Andrew O'Neill said:
The closest maybe would be ammonium citrate, Dibasic? What do you think?

You can make your own with ammonium carbonate (NH4)2CO3 and citric acid. The former is easily (and cheaply) available as Baker's ammonia.

:Niranjan.

Andrew O'Neill · 2025-07-22T16:51:15-0400

nmp said:
You can make your own with ammonium carbonate (NH4)2CO3 and citric acid. The former is easily (and cheaply) available as Baker's ammonia.

:Niranjan.

Thanks! So, Baker's Ammonia can be used in place of Triammonium Citrate?

nmp · 2025-07-22T17:34:05-0400

Andrew O'Neill said:
Thanks! So, Baker's Ammonia can be used in place of Triammonium Citrate?

You still need a source for citrate to make ferric ammonium citrate. Mike's formula uses triammonium citrate so what you do is make it in situ with baker's ammonia and citric acid and then add the ferric nitrate.

You can use this to calculate the amounts (I used 15g ammonium citrate as product which is what Mike's formula requires and the others are calculated automatically):

https://www.webqc.org/balanced-equation-C6H8O7+(NH4)2CO3=(NH4)3C6H5O7+CO2+H2O

Mike requires 40 cc of water to start, the reaction produces 1.67g so you start with 40-1.67= 38.33 cc (or gm) of dist water, dissolve 11.85g of citric acid. Then add 8.9g of Baker's ammonia. Use a large beaker and add very slowly as the reaction will produce CO2 fizz (like Alka Seltzer.) Once the addition is done, you have now 15g triammonium cirate in 40 cc of water. Then add 12g ferric nitrate as stipulated to make Mike's cyanotype part A.

:Niranjan.

Andrew O'Neill · 2025-07-22T18:00:07-0400

nmp said:
You still need a source for citrate to make ferric ammonium citrate. Mike's formula uses triammonium citrate so what you do is make it in situ with baker's ammonia and citric acid and then add the ferric nitrate.

You can use this to calculate the amounts (I used 15g ammonium citrate as product which is what Mike's formula requires and the others are calculated automatically):

https://www.webqc.org/balanced-equation-C6H8O7+(NH4)2CO3=(NH4)3C6H5O7+CO2+H2O

Mike requires 40 cc of water to start, the reaction produces 1.67g so you start with 40-1.67= 38.33 cc (or gm) of dist water, dissolve 11.85g of citric acid. Then add 8.9g of Baker's ammonia. Use a large beaker and add very slowly as the reaction will produce CO2 fizz (like Alka Seltzer.) Once the addition is done, you have now 15g triammonium cirate in 40 cc of water. Then add 12g ferric nitrate as stipulated to make Mike's cyanotype part A.

:Niranjan.

Wow! Thank you for that!

nmp · 2025-07-22T18:16:47-0400

Andrew O'Neill said:
Wow! Thank you for that!

You are welcome. Let us know how that turns out.

Andrew O'Neill · 2025-07-22T18:32:15-0400

@nmp and after adding the 12g of ferric nitrate, I also add the 12g of potassium ferricyanide, correct?

Andrew O'Neill · 2025-07-22T18:33:21-0400

nmp said:
You are welcome. Let us know how that turns out.

Will do, must waiting for Baker's Ammonia to arrive in a few days...

nmp · 2025-07-22T18:43:54-0400

Andrew O'Neill said:
@nmp and after adding the 12g of ferric nitrate, I also add the 12g of potassium ferricyanide, correct?

Yes, if you want to make a One part sensitizer. For a 2 part which should have longer shelf life, Mike suggests make ferricyanide separately with 10g in 50cc of water. For one part, add 10g ferricyanide to the previous solution and add water to 100cc.

Also, let me make a correction/addendum to the earlier formula. It seems Baker's ammonia while they call it ammonium carbonate might actually be ammonium bicarb - NH4HCO3. In that case the balance is:

C6H8O7 + NH4HCO3 = (NH4)3C6H5O7 + CO2 + H2O. - Balanced chemical equation, limiting reagent and stoichiometry

Balance Chemical Equation - Online Balancer

www.webqc.org

Now 15g triammonium citrate requires 14.6g amm. bicarb and (40 - 3.3 = 36.7g or cc water) with 11.85g citric acid.

:Niranjan.

Raghu Kuvempunagar · 2025-07-23T12:10:20-0400

FWIW I have previously prepared Simple Cyanotype sensitiser Part A without using Ammonia directly. The idea is to use Ammonium Chloride and Sodium Hydroxide to in situ generate Ammonia in solution. So, after making a solution of Citric Acid and Ferric Nitrate as per Mike Ware's instructions, dissolve calculated amount of Ammonium Chloride in it. And then add calcluated amount of Sodium Hydroxide solution little by little and stirring well after each addition. When Ammonium Chloride reacts with Sodium Hydroxide, Ammonia is generated which reacts with Ferric Citrate to form Ferric Ammonium Citrate. However, the sensitiser thus prepared contains Sodium Chloride in it as a biproduct of the reaction that supplies Ammonia.

Ammonia / tri-ammonium citrate for Simple Cyanotype

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