RE: [APML] Speeding up film with cold weather

["Richard Klappal" <klappal@xnet.com>]

The origin of the cold camera was the result of E.S.King seeing improvements
in winter vs summer photos "Annals of the Harvard College Observatory"
(1912).  How much it still holds with modern emulsion I haven't researched.
Newton & Teece "The Cambridge Deep-Sky Album" has examples of cold-camera
images.

I thought I had a book with plans for a homebrew cold-camera, but all I can
find at the moment is the 1988 edition of Newton & Teece, "The Guide to
Amateur Astronomy".  It references detailed documentation published in Feb
1981 Astronomy Mag. The earlier heyday of the cold camera was in the
mid-1960s. There are probably references in the S&T or Astronomy archives.

-----Original Message-----
From: owner-astro-photo@seds.org [mailto:owner-astro-photo@seds.org]On
Behalf Of Mark Bohrer
Sent: Sunday, November 03, 2002 14:58
To: astro-photo@seds.org
Subject: Re: [APML] Speeding up film with cold weather


Using Ektachrome ISO 100 slide film at 5AM in Monument Valley a few years
ago, I noticed no difference in exposure at ~20 degrees F versus shots
taken above freezing. I've never noticed a difference in winter photography
in general, either. A lot of photographers would be up a creek if film
speed varied with temperature the way you describe.

Cold temps may buy you less dark noise with CCD-based cameras, but that's
it.


>Hi all,
>
>I know this is not a new concept (cold cameras). I
>remember reading in Splendors Of The Universe that
>film speed effectivly doubles when the temperature
>drops below freezing. I have never really noticed
>this, but am working on new pictures that I can
>compare to pictures I took last month when the weather
>was warmer.
>
>I would like to hear if any of you have ever checked
>this out and done comparisons for yourself. Is this a
>real or imagined effect?
>
>Thanks,
>Alan
>

Mark Bohrer
www.kokophoto.com
Pro mountain bike racing on the web


--  APML Archives at <http://astro.umsystem.edu/apml/>  ---
             Unsubscribe at <majordomo@seds.org>




--  APML Archives at <http://astro.umsystem.edu/apml/>  ---
             Unsubscribe at <majordomo@seds.org>