Jeffrey D. Mathias (jeffrey.d.mathias@worldnet.att.net)
Sun, 23 May 1999 18:44:02 -0400
Witho Worms & Jorien van Santen wrote:
>
> To Jeffrey Matthias,
> Last week I tried your formula for lithiumpalladiumchloride (7.92 / 16.59
> in 100 ml of water) I had good results with better blacks, though I made
> only one test. I missed a lot of mail last weak. Are there changes in
> quantities of the different compounds or are they still the same after
> having done more research.
So far this formula remains supreme. Although I am doing more tests and
the amounts may be reduced slightly (keeping the same amount of water).
However, the relative ratio of LiCl to PdCl2 will and should remain the
same.
> What compounds and what formula's do I need to make pure platinum prints in
> D.O.P and P.O.P. (Zia).
For the traditional Pt/Pd formula using 27% Ferric Oxalate I recommend
the following concentrations of metal salts.
K2PtCl4 24.06%
Na2PdCl4 17.05%
K2PdCl4 18.92%
Note that the K2PtCl4 and the K2PdCl4 will not stay in solution at
standard conditions (25C, 1 atm. pressure). The K2PdCl4 should be
placed in a hot water bath (enough to fully keep it in solution. The
same for K2PtCl4 but it is recommended to not heat higher than a
temperature of 140F. It is thought that higher temperatures may convert
some of the platinum salt to the slightly soluble K2PtCl6 which could
leave specks in the print.
A concentration of 20% for K2PtCl4 works fine (this is the traditional
strength); however I have noted a slight improvement with the higher
concentration. Again the problem being that the higher concentration
will not stay in solution at standard or most normal conditions.
Additionally I would like to ask why you feel that you must work with
100% Pt. In my work I have noticed little difference between 100%Pt and
2/3Pt-1/3Pd. I have rarely printed with more Pt than 50Pt-50%Pd with
the greatest substance and quality (for the papers I use) being achieved
with 1/3Pt-2/3Pd to 25%Pt-75%Pd. Also in my limited experience with
Zia, I have found that perhaps 10% to 20% Pt may be all that's needed to
fully appreciate the advantages Pt can offer. Of course I am in the
midst of testing this. I believe Carl Weese has already stated some of
the benefits of some Pt in the Zia formulas. Perhaps his has found a
threshold for the amount of Pt that's beneficial.
But do remember that there is no absolute formula or mixture that will
give the best or magical results; it's a mater of personal selection.
However there are basic properties that the materials will follow. And
understanding these properties can help immensely with the selection
process.
-- Jeffrey D. Mathias http://home.att.net/~jeffrey.d.mathias/
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