From: Rocky J. Boudreaux (rocky@pdq.net)
Date: 10/28/03-12:17:34 PM Z
RE: Test for Silver Metal in Print?Seeing this post sparked a question in my
mind that I thought I would pass on.
If 80% of the Platinum/Palladium is lost in the standard process, where does
it go?
Where is it lost?
If it goes into the developer then would it automatically act as a toner if
the developer (perhaps Potassium Oxalate) used for the Kallitype developer?
Or does Kallitype require another type developer?
If yes could an old developer enriched over the years be used as a toner for
Kallitype?
Rocky
Houston, TX
-----Original Message-----
From: Sandy King [mailto:sanking@CLEMSON.EDU]
Sent: Tuesday, October 28, 2003 12:14 PM
To: alt-photo-process-l@sask.usask.ca
Subject: RE: Test for Silver Metal in Print?
Hi Philippe,
Thank you for your clear analysis of the possibilities and how to proceed.
As to why I want to know this it relates to a comment made a few weeks ago
by Judy Seigel regarding Pt/Pd toned kallitypes versus straight Pt/Pd. What
Judy wrote was this:
Most casual photo purchasers probably never heard of kallitype, and even
the "savvy" ones would probably confuse it with calotype.... Including the
dealers. (If they actually know the difference they're probably
photographers or historians and not in the market.) In any event, you
might finesse the point by doing what the ancients apparently did... I
doubt there is a non-destructive test to distinguish between the pd print
& pd-toned kalli.... there may not even be a "destructive" test (???).
Which is to say, the medium is what you say it is.
This got me to wondering if there are any actual essential physical
differences in a Pt/Pd toned kallitype and a straight Pt/Pd print. If there
are not such differences, that is if they both consist of nothing but
palladium and/or palladium metal on a paper surface, then my thinking is
that it would indeed be appropriate to label a Pt/Pd toned kallitype as
simply a Pt/PD print. In other words, if the two printing processes produce
an image with identical tonal characteristics, identical physical
properties, and identical archival properties there would appear to be no
functional difference and we would merely have two paths to reach the same
end.
So the question is, of what does a Pt/Pd toned silver-iron print consist.
Does it contain any free silver metal? And if not, has the silver been
entirely replaced during toning, or has it been partially replaced and
partially plated, or entirely plated.
The answer to these questions would be important in evaluating the
potential archival quality of kallitypes toned with the noble metals gold,
palladium and platinum, and would also give guidance as to correct labeling.
This would also have important economic considerations, especially for
platinum printing, because if you could produce a print that consisted of
100% platinum metal with the iron-silver sensitizing method rather than with
the iron-platinum method you would clearly save a lot of money. It takes
about 1/5 as much of Pt/Pd to tone as kallitype as it takes to make a
straight Pt/Pd print, and the difference is due to the fact that about 80%
of the Pt/Pd used in coating is removed during processing.
Let me make it clear that I am not making claims here, just trying to find
answers. But at least I think I now understand how to find the answers.
Sandy
Sandy,
Your question is interesting.
OK, first, you should probably describe your toning formulation so that
we chemists could foresee what is likely to happen. This way we could
probably discard one of the 3 possibilities. Anyway the 3 possibilities here
are:
1/ There is no silver left
2/ You have platinum/gold/palladium plated silver particles
3/ Both silver and platinum/gold/palladium are present and show
free surface
First you can check for hypothesis #3:
Take your reflection density on a given spot in a uniform density spot
on your toned print.
Process your print with rehalogenating bleach (ferri +bromide), as Judy
suggests.
Fix and rinse and dry.
Measure the density again.
If you have a density loss, hypothesis 3 is the right one
If not, hypothesis 3 is wrong. You then have to check for hypothesis 1
or 2.
Therefore, the most straight forward method is indeed X-Ray fluorescence
(very close to EDS but more easy to find closeby I think). You just send
high energy X Rays on a sample, and it reemits low energy X-Rays with an
energy depending on the reflecting material.
Just go in the chemistry of physics departement with a part of your
print to analyse. Ask a 3d year student who's the professor/assistant in
charge of basic training on this technique (also called Coolidge tube
experiment), or a PhD student (they like to play). You will most likely find
it in the Physics departement. Student often try this simple technique
during the first or second year. Just ask to submit your print to the test.
We did it with everything we had at hand.
You will have the Palladium or Platinum or Gold peak, and maybe the
silver peak. If you have the silver peak, hypothesis 2 is true.
If you don't, basecally I would say hypothesis 1 is true with some
assumptions.
My question: why do you want to know it ?
Hope this might help,
Philippe
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