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

[Christina Anderson]

Loris,
I hear you, about VDB and argyrotype.
I switch back and forth between the two processes every semester. Last year I had a bunch of papers that I distributed to the students that were "good for alt" and they were not good for argyrotype. Very disappointing. 
On a side note, this year I went to mix argyrotype for the next day's lab and did not have a key ingredient on hand so the morning of the lab I mixed up a batch of VDB, praying that there would be no problem since it was a fresh solution. There was no problem. Excellent prints, no paper troubles with no aging of solution. And no acidfying of paper. I also had to mix it rapidly (and you know how that goes with VDB, it'll go milky on you with the last additions of silver) but I was using hot distilled water to mix because the lab was imminent and lo and behold, no milky solution either. One of those good days where all things worked out well in a pinch.
Chris

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.
> 
>