Sulfamic Acid for Paper Acidification

[Andrew O'Neill]

At a 1:1 dilution, the smell was subtle. Reminded me of a salad with vinaigrette dressing! I would continue using sulfamic acid, but it's pretty expensive. One pound $10.

 

[Herzeleid]

That is expensive, I buy 1 kg (2,2 pounds) around $6. Once I tried vinegar for cyanotypes, I decided not to use it again

 

[Andrew O'Neill]

I just sourced a 25kg bag of SA for $44 CDN from ClearTech.. and the place is just down the road from me. No more Home Depot!

 

[NedL]

For calotypes, not cyanotypes, I've been using white distilled vinegar mixed 1:2 with water, 1 hour soak followed by 2 hours wash. I covered the tray while the papers were soaking and the smell did not bother me, I even like it a little... slightly fruity But if I had to mix acetic acid from my concentrate, it would be way too much and I'd try SA right away.

After reading this whole thread a couple months ago, I went to the hardware store and found "dry acid" but the box did not say if there were other ingredients besides SA so I didn't get it.

I've been meaning to go to home depot to get some, but the more I think about it, the more I think I will just stick to the vinegar. It works fine for my purpose: no more fogging problems, it's not expensive, and I always have some here anyway. I only acidify 4 or 5 sheets at a time, so cost and volume just don't come into play for me. If I start working in larger quantities, then I will reconsider SA. Just my 2 cents, and only for U.S version of Canson Marker paper and Greenlaw's calotype process.

 

[Andrew O'Neill]

If you have tested it, how long did it take to neutralize the paper?

I left it (11x15 inch sheet) in for 5 minutes. Gave it a thorough washing afterwards.

 

[Herzeleid]

I left it (11x15 inch sheet) in for 5 minutes. Gave it a thorough washing afterwards.

If you can test it with modern cyanotype or argyrotype that would be very informative. I think they are the ideal processes for benchmark. Most of the siderotypes are usually improved after acid treatment, but modern cyanotype and argyrotype demand the most out of papers.

 

[Herzeleid]

For calotypes, not cyanotypes, I've been using white distilled vinegar mixed 1:2 with water, 1 hour soak followed by 2 hours wash. I covered the tray while the papers were soaking and the smell did not bother me, I even like it a little... slightly fruity But if I had to mix acetic acid from my concentrate, it would be way too much and I'd try SA right away.

After reading this whole thread a couple months ago, I went to the hardware store and found "dry acid" but the box did not say if there were other ingredients besides SA so I didn't get it.

I've been meaning to go to home depot to get some, but the more I think about it, the more I think I will just stick to the vinegar. It works fine for my purpose: no more fogging problems, it's not expensive, and I always have some here anyway. I only acidify 4 or 5 sheets at a time, so cost and volume just don't come into play for me. If I start working in larger quantities, then I will reconsider SA. Just my 2 cents, and only for U.S version of Canson Marker paper and Greenlaw's calotype process.

I didn't had the chance to try calotypes, I just know it requires papers without alkaline content. IMO 2 hours wash is a bit long, may be you can test and find a shorter washing time for it. Considering that the 1:2 vinegar is mildly acidic, it should not require a long wash (also calcium acetate is highly water soluble). I am hoping to try calotypes sometime with the same papers washed in SA.

SA dissolved it water also has a very long shelf life, I am re-using the %10 solution until it exhausts or starts to act too slow for my liking.

 

[Film Guerilla]

For the hell of it, I acidified a sheet of Stonehenge in a bath of vinegar, diluted 1:1. Worked very well. Vinegar is heaps cheaper than sulfamic acid. Not yet sure of it's capacity, though, so more testing to do.

Hi Andrew, i've had tested vinegar before and i had good prints using modern cyanotype. The first workflow i made was 1:1 water/vinegar atleast 10mins presoak and then wash. The second batch i made with different workflow has some problem. Not sure i got some white spots on the prints. I think i presoak my papers for almost 1 hour then wash. I'll try to print again soon so it would be helpful if i could get some other tips. How do you wash your papers? Minutes? Procedure with presoaking would be nicE. Thanks!




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[NedL]

...IMO 2 hours wash is a bit long, may be you can test and find a shorter washing time for it.

Thanks Herzeleid, that is a good idea.

 

[Andrew O'Neill]

Film Guerilla, I only soaked it in vinegar for 5 minutes and left it to wash for about an hour in a tray with a kodak syphon.

 

[Loris Medici]

If you can test it with modern cyanotype or argyrotype that would be very informative. I think they are the ideal processes for benchmark. Most of the siderotypes are usually improved after acid treatment, but modern cyanotype and argyrotype demand the most out of papers.

I wonder how does untreated Stonehenge works; a good test would also include a heavily buffered paper such as Fabriano Artistico.

 

[Film Guerilla]

Film Guerilla, I only soaked it in vinegar for 5 minutes and left it to wash for about an hour in a tray with a kodak syphon.

I read some peopLe after pre soaking their papers they dont wash it anymore. Isnt it 1 hour too long for washing? I'll try it soon. Thanks


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[Loris Medici]

I read some peopLe after pre soaking their papers they dont wash it anymore. Isnt it 1 hour too long for washing? I'll try it soon. Thanks

If you don't intend to store the paper for long term that's probably not a big deal - as long as you keep the papers in a relatively dry environment. OTOH, the presence of acid will definitely have some effect on the printing process - not necessarily harmful, but may affect your calibration... I prefer to wash the papers after dealkalinization, I don't like the idea to keep the acid in the paper...

 

[Film Guerilla]

If you don't intend to store the paper for long term that's probably not a big deal - as long as you keep the papers in a relatively dry environment. OTOH, the presence of acid will definitely have some effect on the printing process - not necessarily harmful, but may affect your calibration... I prefer to wash the papers after dealkalinization, I don't like the idea to keep the acid in the paper...

Thanks Loris! How you guys wash your papers? Just curious if i use the same way how i wash silver gelatin paper wouldbe fine.


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[Andrew O'Neill]

Yes, just wash as you would with silver gelatin papers. I have two vertical washers and can wash up to 20x24 sheets. I don't really like handling 22x30 sheets of paper as very easy to crimped and/or tear, so I cut them down to 15x11. I'll only acidify larger sheets if I'm planning on making a 16x20 kallitype.
I've got a wack of fibre-based gelatin silver paper (old oriental and ilford mg vc) that I've fixed out. No need to acidify these papers as they give beautiful tones. I sensitize the backside. I like these papers as they have a very nice smooth surface.
Just picked up 25kg bag of sulfamic acid, and 25kg bag of sodium thiosulfate (anhydrous) from local chemical supplier. Very cheap. Very happy!

 

[SMBooth]

Just reading this out if general interest but how does one know if the paper needs acidification?

 

[NedL]

Just reading this out if general interest but how does one know if the paper needs acidification?

In my case, the calotypes were badly fogged all over, front and back, when I developed them.

Acidifying the paper solved this problem, however my last attempt had light fogging and I don't know why. Possibly from storing the papers between blotter that might be alkaline.

 

[Vaughn]

A weak-looking print that you can't seem to improve is a sign of a paper that maybe highly alkaline sized. But some papers will print nicely untreated -- and wonderfully when treated. One may need to tweak the ratio of the number of drops, as the contrast may change (increase) a little. Seems like a richer black is possible. If one is going to try treating paper, might as well run the test on several nice-looking papers. Some do not need it -- such as COT320.

Is there an indicator dropper test that one could use on a new paper -- just to see if the paper deviates from neutral in either direction?

 

[SMBooth]

OK thanks.
A dropper test would be Vaughn.

 

[Herzeleid]

Cut a small piece of the paper you want to test. Put the paper in a beaker filled with strong acid.
If you see fizzing, bubbles that means an acid-base reaction going on and that paper contains alkaline buffer.

It would be better than dropper test.

Ph indicator solutions are a possibility but I don't know any indicator solution that would give such distinct colors within a small ph range.
Bromocresol purple gives yellow in acidic conditions, purple in neutral and also purple in alkaline. Usually they are only helpful to determine acidic or alkaline conditions very hard to distinguish neutrality.

Another option to test is to use modern cyanotype formula. In alkaline conditions the coating will turn green in a very short time. In neutral, buffer free papers the coating stays yellow for at least 24h under right temp and low humidity. If the paper is not rinsed after acid treatment, as you coat the paper you can smell the nasty chemicals, not recommended.

 

[Vaughn]

I do not rinse the paper after acid bath when making platinum prints -- no smell with that process.

 

[Tetium]

Hi everybody,


First I want to thank you for this incredibly interesting thread !


For my projects with cyanotype I want to optimize my processes and give a try to the acidification method with sulfamic acid.


Actually I’m a bit lost with the process with SA…
Is somebody can tell me what is the exact procedure to work with SA and cyanotype ?


If I understand, in order to acidify my paper I have to :
1 - Pre-soak my sheets in water,
2 - Immerse the sheets in 1M sulfamic acid solution,
3 - Thoroughly rinse this in tap water in order to make the paper free of acid.


And then, I can work with my cyanotype. (Am I right ? - or am I missing something ?)


I would like to know what to do after when my cyanotype is exposed.
Do I have to clear my paper in an other bath of sulfamic acid to avoid any re-alkalization ? (my tap water is slightly alkaline)


If yes, what concentration should I use in my final bath ? (1% ? - less ?)


Thank again, and sorry for my english.

 

[Herzeleid]

Hi Tetium,

I thought I have posted a response. But it does not appear here, sorry for the late response

The procedure is very simple. There is no need for pre-soaking in water.

1 - Immerse the paper in 1M sulfamic acid solution. Depending on the paper it can take up to 20mins to dissolve entire alkaline content.
2- Wash the papers thoroughly to remove all the acid.

That is it. There is no need for another sulfamic acid bath.

If your tap water is too alkaline there are other methods to de-chlorinate the tap water.
But if your prints are bleaching in the final wash you can make it %0,5-1 sulfamic acid.
But I cannot say that would be a good practice from the archival perspective.

Regards
Serdar

 

[ced]

Resurrecting this thread...
Anyone tried SA presoak with Kallitypes?

 

[SMBooth]

Resurrecting this thread...
Anyone tried SA presoak with Kallitypes?

Yep if the paper needs it, doesn't affect anything else in the process.