Re: Silver sensitization w/ NH3?

John Rudiak (wizard@laplaza.org)
Fri, 27 Sep 1996 16:45:16 -0600 (MDT)

On Wed, 25 Sep 1996 SCHRAMMR@WLSVAX.WVNET.EDU wrote:

> Tox,
>
> Some astrophotographers I know use gas hypered film which gives them
> an extra couple of stops but I don't know what the gas is. It could be
> ammonia. I do specifically remember reading about supersensitizing film
> by using mercury vapor, I'll see if I can look that one up.
>
> Bob Schrann
> Schramm
>

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).

Any one else?

John