[alt-photo] Re: dilution of pt/pd

[EJ Photo]

Terry, I am not over complicating anything. As to teaching print making
during a workshop, that is the point of them with the materials at hand. 

The Zia system, which introduced lithium and cesium to the mix of the
platinum printing options, has questionable linage. The first formula were
off and to once again use the formula provided would produce unbalanced
solutions. A simple check, with proper mixing at molar concentration show
improved results. Let's just say it another way to fact check and one that I
prefer for solutions used in noble printing than use of percentages. 

With the knowledge of the formulas and the ability to check the molarity of
them, I was easily able to fix them. This repair would not have been
possible with simple percentages. 

With the knowledge of simple chemical equations, one is able to confirm the
accuracy of many early photo formulas and even those passed along by modern
practitioners. I'd even go so far as to say that teaching of percentage
based solution is a disservice to the student and prolongs their use of
kits, like those being sold by B&S, by keeping the training wheels on the
thinking of the platinum palladium printing process.   

Again, we have a situation where a change in proper the language was made
from "to make" to "add to". 

And to take this a little further, what do you have in units when you take
three different compounds and add them to water and then mix them together?
How do those three different percentage solution work together? If I make
two solutions 1/2 as strong as the third, where the third is used twice as
much as during the process? The failing of the percentage based conversation
is that it breaks down when explaining how the solutions work together in
whole units. 

Enjoy your basket of fish n chips, a few of us are taking some people down
to the water and catch some fish. ; )  
 

Eric Neilsen
Eric Neilsen Photography
4101 Commerce Street, Suite 9
Dallas, TX 75226
 
www.ericneilsenphotography.com
skype me with ejprinter
www.ericneilsenphotography.com/forum1
Let's Talk Photography
 
-----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
Terry King
Sent: Thursday, July 22, 2010 6:56 AM
To: alt-photo-process-list at lists.altphotolist.org
Subject: [alt-photo] Re: dilution of pt/pd

Dear Eric


You don't need the over-complication of molar based solutions, it can be
done just as effectively with a percentage solution if not more so. All you
need to do is ensure that you are applying enough solution at the right
dilution.


People have been getting good rich platinum blacks that way for 140 years !



Terry






It seems to me that the main point of making concentrated and molar-balanced
solutions of palladium(or platinum) and ferric oxalate is to ensure that
there will be sufficient concentrations of the solution per square inch of
print to yield a really deep black in those areas where the exposure is
complete. 







-----Original Message-----
From: Eric Neilsen Photo <ejnphoto at sbcglobal.net>
To: 'The alternative photographic processes mailing list'
<alt-photo-process-list at lists.altphotolist.org>
Sent: Thu, 22 Jul 2010 3:40
Subject: [alt-photo] Re: dilution of pt/pd


I'd also camp under that flag. Diluting the coating solution can be OK, but
it doesn't take too long before the production of a viable black is
impossible. Balance is the key; extra solution may NOT be extra all, just
what is required.   

-----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
Clay Harmon Website
Sent: Wednesday, July 21, 2010 5:04 PM
To: The alternative photographic processes mailing list
Subject: [alt-photo] Re: dilution of pt/pd

I have accidentally printed on a piece of paper coated with a 50% diluted
coat of palladium and ferric. The result was an anemic black and a generally
weak print. It also was badly solarized on the edges where the brush strokes
tailed out. This squares with my observation that solarization is most
likely to occur where there is too much exposure of too little coating in
the paper.

It seems to me that the main point of making concentrated and molar-balanced
solutions of palladium(or platinum) and ferric oxalate is to ensure that
there will be sufficient concentrations of the solution per square inch of
print to yield a really deep black in those areas where the exposure is
complete. Unless you print on completely wet paper, the water portion of the
solution has evaporated and all that is left is the solution, the paper
fibers, and whatever residual humidity from the coating solution remains in
the paper fibers. 


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