Richard Sullivan (richsul@earthlink.net)
Thu, 13 May 1999 15:43:25 -0600
>if Jefferey is correct then I guess I will have to buy shares in Bostick &
>Sullivan. <G>
>
> Tony McLean
Hmmm an IPO coming up???
It may be of interest to describe how I arrived at the Zia formula originally.
The magic ingredient in the Ziatype is the lithium chloropalladite. My
original adventure was to explore the exotic double palladium salts. We
commonly use the sodium palladium salt. The ammonium palladium is used on
occasion, notably in the Ware system. It can be a pretty boring trip. I
tried with varying degrees of success (some just made a brown mess)
zinc-pd, barium-pd, potassium-pd, tin-pd, strontium-pd, and a scad of
others. If the combo didn't produce an insoluble precipitate it usually
worked producing a nice brownish black print. At this stage I was going
back and forth from the Anderson formula and the Pizzighelli POP formula
its Ware variation.
One day as I was eating my lunch in the lab and reading Mellors on
Chemistry I came across the mention that lithium chloride was the most
hygroscopic substance known. This hit me right away and I immediately
thought of the Pizzighelli process. I called Spectrum and ordered some LiCl
overnite pronto.
The first print was a stunner. Cold dead black, not a hint of brown. It had
a great dmax as well. None of the other pd-combos produced a neutral color.
In fact there appears to not have been a historical material using pd that
was neutral. In the Whaley bio of Steiglitz, it is mentioned that A.S. was
quite distraught when platinum paper went off the market and he was forced
to use palladium. A.S. did not like the brown color of the pd paper at all.
Had there been a black pd paper, A.S. would likely have known about it, he
was a pretty well connected dude after all.
In refining the Lithium Pd POP system I first made some chemical
calculations and I admit I could have made some errors. (My original notes
went back to Seagate with a drive several years ago.) I then made a ton of
test strips with Stouffers wedges and a ton of prints varying the ratios of
Pd to AFO to H2O. I found wide areas where varying the ratios made no
apparent differences in image quality. (I have to admit my testing
procedure was no quite as objective as Tony's with an independent observer
attached.) My next step after discovering the plateau was to back off on
the pd until degradation in image quality occurred. At this point I added
Pd back in until the image quality returned and then added a little more
for safety. In other words, the formula was optimized for economy. Oddly
enough, after arriving at the formula, the amount of actual Pd metal in the
emulsion is almost exactly that of the Anderson (standard developing out)
formula.
It is quite possible with a testing regime like this, certain variables
like paper, coating technique, and living in a partial vacuum, could tilt
the results one way or another.
I also have a whole bunch of curves etc that I did for The New Platinum
Print that are in a hidden directory on my web site. I might dig these up
and make them public if anyone is interested. There are two points of
interest shown by the curves. One is that the Ziatype truly contrast
controlled whereas the Anderson method is only highlight restrained. The
other is that it is virtually impossible to solarize the Ziatype. Only
after better than 3 hours of exposure did some hints of it showed up.
A note: Later experiments show that magnesium palladium chloride produces
results very similar to the lithium palladium chloride. It prints with a
teeny hint more brown to the black, oh so very slight! But then I am
severely color blind so what do I know.
--Dick Sullivan
505-474-0890 FAX 505-474-2857
<http://www.bostick-sullivan.com>http://www.bostick-sullivan.com
http://www.workingpictures.com
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