Keith Schreiber (stillpoint@worldnet.att.net)
Thu, 18 Feb 1999 00:54:19 -0700
My cousin is an astronomer - the Levy half of the team Schumaker-Levy that
has discovered a bunch of comets including the one that plowed into Jupiter
a couple years ago. Anyhow, I had heard David mention "hypering" his films
on several occasions and had wondered how it worked. They use "hypered" Tech
Pan and a typical exposure runs 8-10 minutes on the telescope we used on the
night I visited last week.
The following is a quote from "The Film Developing Cookbook" by Anchell and
Troop (p.93):
Gas-hypering has been dramatically successful with Kodak 2415 (Tech Pan)
and other contemporary monochrome and color films. Before exposure, the film
is soaked in a forming gas mixture of 92% nitrogen and 8% hydrogen for
several hours. The hypersensitization effect can last for years if the film
is properly stored (earlier hypersensitization techniques only worked for a
few hours). Astronomers, working with exposures that may run into the hours,
report reliable and dramatic speed increases as well as reduced reciprocity
failure with long exposures. For example, with gas hypered film a night sky
photograph that would formerly take four hours can now be made in 30 minutes
or less. With conventional exposures, shorter than one second, the maximum
speed increase you can expect is one stop ....
Hope this helps,
Keith
-----Original Message-----
From: jewelia <jewelia@erols.com>
To: alt-photo-process-l@sask.usask.ca <alt-photo-process-l@sask.usask.ca>
Date: Wednesday, February 17, 1999 10:19 PM
Subject: Hypersensitize me up scottie!
>one of the first things i learned about this list was ebay.com -- i haven't
>bought anything yet cause i suppose nobody has offered to sell my color of
>lipstick: however, i did notice this thing called a hypersentizing system
on
>the auction block--i had no idea what it is and thinking it might be made
of
>latex i clicked on it out of curiosity. turns out the seller was good
>enough to list the web site of the maker lumicon.com. the gist of it is
>interesting--the idea is to treat chemically to raise its speed--whether
>color or B&W. apparently, the target market is astronomy--or was it
>astrology--i always get these mixed up! it is supposed to raise film speed
>by a factor of about 10. i looked at the systems--you can buy systems to
do
>it yourself or you can buy film--the company sells mostly optics--scopes
and
>telescopes and apparently a major customer for this stuff is astronomy.
>
>they don't have a system big enough for 8x10 so i sent off an e-mail asking
>if i could build my own and buy their chemicals if i wanted to do it--from
a
>technical standpoint--they wrote back today and said something to this
>effect: you need a vessel that can maintain a vaccuum of 27-30" or 15 psi
>(i know it seems confusing to me--but i am guessing both not at the same
>time) and can be heated to 50 degrees (i assume this is centigrade) .for
>several days best to use a rack to hold the sheets seperate. i asked them
>what the effect would be on film grain and resolution and their response
was
>none that it pretty much only effects reciprocity--sounds to good to be
>true? actually reciprocity and i are good friends and get along very well
>but i was wondering if there are any astrophysicists or other lunars out
>there who have any experience with this? have i been in the dark room by
>myself too long?
>
>regards--jewelia
>
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