Jeffrey D. Mathias (email@example.com)
Wed, 28 Jul 1999 07:34:52 -0400
Gary Miller wrote:
> Today I bought some Arches Platine and did a few Pt/Pd tests. I used 11
> drops to cover a 4x5 area. The mixture used was 5 drops of solution 1, 1
> drop of solution 2, 3 of Pd, 2 of Pt, and sometimes 1 drop of Tween 20
> (10%). All four samples that I did were exposed for different times ranging
> from 11 mins to 16 mins, and all showed reversal/solarization in the darkest
> areas. I even see this solarization in most of the numbers on my step wedge
> and the beginning, top, part of the wedge up to about step four is totally
> obliterated/solarized. Is my exposure too long. The 11 min one looks fine
> otherwise with detail throughout,even in the brightest highlights. The same
> formulation used on Cranes Platinotype had an exposure time of 16 mins.
> Both were developed in potassium oxalate at 85F, and cleared the same. Any
> advice would be greatly appreciated before I do some more tests with shorter
> exposures. Could there really be such an exposure time difference between
> these two papers?
I have not noticed any significant exposure difference between Crane's
and Arches Platine. As Keith, I question your chemistry mix. He also
makes a good suggestion to test the Crane's to see if it still behaves
the same (a reference).
I do not know what your solution 1 or solution 2 are and to what
metal salts are mixed. I do know that solarization can be affected by
the solution mixtures as well as temperature, humidity, coating
technique, and exposure.
Since I have used Arches Platine and have not had a solarization
problem, I would suggest using the chemical working solutions presented
in my Guide (web site below). There is always the possibility that this
was a "bad" batch of paper.
Another possibility is that the negative requires too much exposure. It
may be too dense or have too little contrast (requiring too much
contrast agent). As with your "11 minute" print, this could produce a
good print, but with solarization in the step wedge and the boarders.
-- Jeffrey D. Mathias http://home.att.net/~jeffrey.d.mathias/
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