RE: Platinum/Palladium & Paper Speed

Mark, One of the primary chemicals that is part of the process is water. I'd
check to see how it is being affected by the procedures being used. Was the
paper humidified before exposure? What type of contact frame was used to
make the exposure? Vacuum or split back? Sealed unsealed with regard to a
vapor barrier between the glass/neg/paper/backing? Heat level during
exposure?

Which of these inhibit the movement of water, and which accelerate or
facilitate it? Is it localized?

And then there is the light source. or UV rays. How are they passing
through the paper? During exposure as well as after when the image is formed
and being revealed to the eye as a reflected image?

If it were true in other processes, are they also using FO, and/or AFO?

Have you put this question to Mike Ware? He at least did some scientific
study of the PT/PD process which was published years back. Perhaps, he can
give you some additional insights.

Eric

Eric Neilsen Photography

4101 Commerce Street

Suite 9

Dallas, TX 75226

http://e.neilsen.home.att.net

http://ericneilsenphotography.com

  _____

From: Ender100@aol.com [mailto:Ender100@aol.com]
Sent: Monday, May 29, 2006 11:42 AM
To: alt-photo-process-l@usask.ca
Subject: Platinum/Palladium & Paper Speed

Has anyone proposed a reason why some papers print faster or slower (shorter
or longer exposure times) than others when printing with Platinum/Palladium?

It would seem to be some chemical related issue, such as buffering or ph of
the paper, but I am only guessing.

I would assume this is also true for many other processes?

Can anyone suggest a reading reference on this?

Thanks in advance.

Best Wishes,
Mark Nelson
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Precision Digital <http://www.precisiondigitalnegatives.com/>
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Received on 05/29/06-12:23:15 PM Z