Re: ziatype

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From: Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Date: 10/07/01-06:16:02 AM Z


Salvatore Mancini wrote:
> Could some kind soul out there inform me as to the correct precentage
> solution of Ferric Ammonium Oxalate I need for Ziatype?

First off, you should be aware that this is only a variation of the
Platinum/palladium process. Typically one would use ferric ammonium
oxalate sensitizer and a lithium/palladium double salt and some humidity
as a Printing Out Process (POP) for this particular variation. But
there are many other variations.

The correct solution strengths and amounts can be determined from a
wealth of information I have personally verified and documented in my
Guide to Platinum Palladium Photographic Printmaking available on my web
site at the link below.

Studying the sections on coating should reveal that the "correct"
percentage can be a function of many factors. This guide, including
several studies, sections on coating, and even formula calculators
should help one determine not only suggested solution strengths for
particular variations, but methods to determine these strengths based on
their own personal criteria, materials, and techniques.

I would caution that just using some percentage may not be the "correct"
percentage for someone's personal situation, and should at a minimum be
verified with a simple optimization study. Another suggestion is that
it is better to error with a little too strong solution as this will be
appropriate for a wider range of situations, but there can be the
situation of too strong which can cause problems. Too weak of a
solution is a very common problem resulting in weak or weaker prints.

-- 
Jeffrey D. Mathias
http://home.att.net/~jeffrey.d.mathias/


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