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(meteorobs) Hypering and meteor photography
A question arose some time ago re: hypering film for meteor photography. The
issue got raised that hypering is a bad idea becausee hypered film is so
volativle and meteor photography so intermittent. Here's a note from the astro-
photography mailing list about how to KEEP hypered film hypered... Not easy!
Clear skies (and films),
Lew
------- Forwarded Message
Date: Tue, 17 Sep 1996 13:57:29 -0700
From: Brad Wallis <wallis@pepe.jpl.nasadot gov>
To: astro-photo@nightskydot com
Subject: Re: [APML]: Questions
The Astro-Photography Mailing List
------------------------------------
>1. What happens to color film after hypering? In other words when is it
>no longer considered hypered? Does it still work normally?
It loses some speed .. but the fog level increases ... becomes mostly useless
film.. OK for taking vacation pics <G>
>2. Can hypered film be re-hypered?
NO .. you'd only add more fog ...
>3. Is it better to store color hypered film in (a) Freezer (b) Fridge
> (c) vacuum?
BEST STORAGE METHOD so far published or discussed ...
-> storage in freezer in Nitrogen ( storage in VAC in freezer should be
equivalent )
mostly you want to store the film cold and DRY .. so in fridge in DRY AIR would
be OK .. or in fridge in DRY N2 would be best ... Freezer is best for short
term .. some recent flak has surfaced about long term storage in freezers...
I have not had time to look into this but tend to not believe the flak ...
You can seel the film in a double zip lock bag ... with air or N2 and put in
a container of silica gel to help keep the film dry ... if you use INDICATOR
SILICA GEL you can see how long it takes to get the S.G. saoking wet ...
you can dry the silica gel either in the oven or in a VERY capable HIGH
VACUUM system ... ( not a hand pump ... not a marvac... )
Brad Wallis
http://voltaire.csundot edu/wallis_provin.html
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