From: Greg Schmitz (gws1@columbia.edu)
Date: 04/08/03-05:13:25 PM Z
Scott:
I don't want to rain on your parade, but it has been my experience
that it is almost impossible to raise the true speed of any film - no
matter what. I have exposed and developed hundreds, perhaps thousands
of rolls of test film. In reality what is usually meant by an
"increase in speed" is really an increase in contrast. The point at
which the films curve begins to pivot upward does not change, it just
gets steeper. I have seen minimal increases in true film speed with a
few special additives, pre/post-exposure, and exposing film to certain
gas fumes.
Depending on what your criteria are for your negative you may well
find that your final results are lower than that stated by the
manufacturer. I base my film tests directly on the requirements I
have for a given type of positive and frequently rate the films' speed
differently for the process that I am using to produce the final
positive. My standard exposure for Tri-X 135, for example, is usually
either 200 or 320.
-greg schmitz <gws1@columbia.edu>
On Mon, 7 Apr 2003, Scott Wainer wrote:
> Hi all,
>
> Having just bought some Arista Pro 125 (aka, Ilford FP4+) I decided to run
> some film speed tests. I tried Crawley's FX-37 developer, Kodak Xtol, and
> D-76/ID 11 and ran into what I consider a problem. All of the developers
> indicated an EI of about 12-25 with standard development using a B+W
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