From: Sandy King (sanking@clemson.edu)
Date: 11/29/01-08:22:58 PM Z
Judy Seigel wrote:
>
>I don't know the Weese & Sullivan method, but I would assume you could
>adapt the Post-Factory (Issue #1) white-card method to pyro. Expose, &
>develop a 21-step in pyro, print in your chosen medium, then read your
>pyro-developed negative against that. (Sandy: Yes? No?)
Yes, that would be the best way to actually determine the ES of your
printing medium with the type of negative being used. Even better
than a densitometer.
> But I note that in
>the article Sandy says you can read the pyro neg in the blue channel of a
>color densitometer, or with filter on b&w densitometer...
Reading a negative of step wedge developed in a staining developer
gives you a much better approximation to the printing contrast of
that negative than by reading the negative through a B&W
densitometer, or through the full color spectrum of a color
densitometer. However, even the blue channel does not fully reveal
the printing contrast of the negative with alternative process as it
is actually somewhat higher than the blue channel indicates.
On the other hand, for printing with VC papers the actual printing
contrast of density of a stained negative is somewhat less than the
blue channel indicates. This fact explains why Carl Weese gets double
duty from his negatives that serve for printing in silver but also in
Pt/Pd. Or at least that is how I understand the question.
Sandy King
>
>Judy
>
>.................................................................
>| Judy Seigel, Editor >
>| World Journal of Post-Factory Photography > "HOW-TO and WHY"
>| info@post-factory.org >
>| <http://rmp.opusis.com/postfactory/postfactory.html>
>.................................................................
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