Re: Silver sensitization w/ NH3?

Sil Horwitz (silh@iag.net)
Fri, 27 Sep 1996 22:31:52 -0400

At 08:51 AM 960928 +1000, you wrote:

>I remember in grad school presensitizing film with hydrogen peroxide
>vapors, to get and honest 1 1/2 to 2 stop increase in speed, relative to
>shadow density. Don't remember much more than that, but do remember that
>we also increased film speed with a preexposure to green light before
>camera exposure (the pre exposure was at sub threshhold level).

Up to now, I have kept out of this discussion because I really don't think
it's pertinent to our basic content of alt-photo. But I'm jumping in to make
the point that modern films are not happy with any type of pre- or
post-hypersensitizing. The older films were very slow, had an equally low
fog point, and could use the boost. Modern films are right at the fog point
on the curve to get max speed. Now let's drop it.

Sil Horwitz, FPSA
Technical Editor, PSA Journal
silh@iag.net