Eric Neilsen (e.neilsen@worldnet.att.net)
Wed, 28 Jul 1999 14:11:17 -0500
"Jeffrey D. Mathias" wrote:
> 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
> Parchment (Platinotype)
> 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
> solution your
> 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.
Gary, Both Keith and Jeffrey make good points. There are several things that you
need to let us in on for more help. How do yo dry your paper? Air dry with heat
or no heat? If you use a blow dryer with heat, you may be getting it too hot. If
you are not using heat, and just air, it could be that the paper has absorbed the
coating solution too deeply, both look somewhat like solarization. Concentration
of coating solutions is important to know, and coating technique.
With the volumes of coating solution, my first guess is that you have a bad drying
technique.
EJ Neilsen
-- Eric J. Neilsen 4101 Commerce Street, Suite #9 Dallas, TX 75226 214-827-8301 http://home.att.net/~e.neilsen
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