[Alt-photo] Re: Sulfamic Acid for Paper Acidification

[Serdar Bilici]

Hi Christina,

In terms of papers, Canson Montval 300gsm and Schoellerschammer Dura Matt
180gsm (drawing paper, 300gsm is better both are hotpressed ) were the
cheapest papers I tested.
And I must say Canson Montval is overall a great performer with new
cyanotype and argyrotype after SA treatment. I am a bit tired of its texture
but it performs quite well with almost anything I have used it for. I ran
out of schoellerschammer so I did not continue testing it, but I had one of
the best double coated untoned VDBs with that paper(300gsm) in terms of
dmax.

I should start making a list of cons and pros of the acids I tested, and
post later as a separate post.

Regards
Serdar



 
-----Original Message-----
From: alt-photo-process-list-bounces at lists.altphotolist.org
[mailto:alt-photo-process-list-bounces at lists.altphotolist.org] On Behalf Of
Christina Anderson
Sent: 05 Mayıs 2013 Pazar 17:19
To: alt-photo-process-list at lists.altphotolist.org
Subject: [Alt-photo] Re: Sulfamic Acid for Paper Acidification

Dear Serdar and Loris, etc.
This is really great news! Thanks for this discussion.
I just finished the semester as of yesterday (thank heavens for summer
vacation), teaching a new batch of alt students. I had a discussion with a
couple of my top students how to make the class better and one of the very
important points they brought up is to limit the class to specific papers
that are known to work--say, three--to make it easier. I would say that
inappropriate paper is the top reason prints fail.
This semester I have been having the students (to save money) acidify their
paper with the available stop bath in the lab and that has worked well
enough to save them money and not introduce another chemical in the
darkroom, but sulfamic acid is so cheap and readily available I could see
having a container of that easiiy in the darkroom. I do not have HCL in
there for obvious reasons.
It is so useful when people share their current top tidbit of the month to
the list! Learning continues.
Serdar, do please share your notes on comparing the acids.
Chris

Christina Z. Anderson
christinaZanderson.com

On May 5, 2013, at 4:51 AM, Loris Medici wrote:

> Hi Serdar,
> 
> The evaluation depends on the process too; for instance, pt/pd is more 
> forgiving about the acit pre-treatment operation but new cyanotype and 
> argyrotype aren't. A paper treated in HCl would work OK with pt/pd but 
> not OK witj new cyanotype or argyrotype. I'm personally more 
> interested in the latter right now, I wasn't printing argyrotype much 
> because it was more demanding (than vandyke) about paper, now that I 
> make it work with many papers, I'm about to dump vandyke forever in favour
of  argyrotype...
> Sulfamic acid pre-treatment made quite difference for me, because when 
> it works (or you make it work with sulfamic acid), I find argyrotype 
> being a lot better than vandyke in every aspect. (Dmax, tonal range 
> and smoothness,
> hue...)
> 
> Regards,
> Loris.
> 
> 
> 2013/5/5 Serdar Bilici <sbilici at gmail.com>
>> 
>> Hi Loris,
>> 
>> I agree that there might be a sweet spot for dmax with HCl, but 
>> really
> why fiddle :)  Sulfamic acid has a great advantage at storage, it is 
> not as corrosive as HCl to metals, so it is safer to work indoors, the 
> prints have better dmax in comparison.
>> 
>> (You already know this bit, but I should include it for other 
>> readers) When I made a research about sulfamic acid and its uses, I 
>> have found out
> that sulfamic acid is used in modern descaling systems to remove 
> calcium deposits instead of HCl. Due it is less corrosive but it has 
> equally strong acidic nature. As you said, probably sulfamic acid 
> leaves the paper in better condition compared to HCl due to its less
corrosive nature.
>> 
>> In terms of dmax, HCl treatment gave me the poorest results among the
> acids I have tested. Although, it was the right choice theoratically, 
> (being a mono-acid, highly water soluble byproduct, fast reaction, 
> good
> capacity) practically the results were not so appealing. Considering 
> that the fumes of HCl would corrode the metals in the room it is used 
> in time, I understand why it is not the most popular choice to acidfy 
> papers. Proper ventilation is quite important when working with HCl 
> (Dangerous chlorine gas release), on the other hand Sulfamic Acid + 
> Calcium carbonate reaction produces only CO2 gas.
>> 
>> Compared to HCl it is a WIN-WIN.
>> 
>> Regards,
>> Serdar
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