Re: [APML] Speeding up film with cold weather

["John C. Mirtle" <jmirtle@shaw.ca>]

Alan;
    There is no question that cold temperatures (and cold cameras) have a
positive effect in reducing low intensity reciprocity failure - but only
with some films. I have logged many hundreds of hours with a cold camera but
have not used it much over the last 5 years or so. With some films, like the
older Ektachrome 400 the speed increase was more like a factor of 6, and it
controlled the colour balance. Green background skies were gone, unless you
were dumb enough to try and shoot through aurora. (a Canadian pastime)
Generally, what I found was that films that hypered well didn't respond to
the cold, films that didn't hyper did. Most responsive to cold cams was
Kodak film, followed by Konica and Fuji generally sucked.
    Films that responded well to the cold were Tri-X, Ektachrome 200 and
400, Gold and Royal Gold 200, 400 and Konica 400. Films that don't change
performance are tech pan, PJM, Fujichrome 400 and 1600 and the Fuji Reala 4
layer stuff gave me my first blue M42. Most films are either gone or have
been reformulated since I was last active with dry ice, I don't know how the
current crop of films work. If you notice a film that seems to "perk up" in
winter, please post your results. Clear nights are so rare around here that
it would be nice to have a short list of films to test, rather than going
through them all.

Some cold camera shots on my web site:
http://members.shaw.ca/jmirtle/double.htm
http://members.shaw.ca/jmirtle/hubble.htm
http://members.shaw.ca/jmirtle/m17.htm
http://members.shaw.ca/jmirtle/m20.htm
http://members.shaw.ca/jmirtle/m27.htm
http://members.shaw.ca/jmirtle/m42.htm
http://members.shaw.ca/jmirtle/m52.htm
http://members.shaw.ca/jmirtle/wveil.htm
http://members.shaw.ca/john.mirtle/eveil.htm
http://members.shaw.ca/john.mirtle/m16.htm
http://members.shaw.ca/john.mirtle/m93.htm
http://members.shaw.ca/jmirtle/coldcam.htm

The effect is real, not imagined. (with some films!)

John Mirtle
Calgary, Ab. Canada

----- Original Message -----
From: "Alan Voetsch" <critter12952@yahoo.com>
To: "APML" <astro-photo@seds.org>
Sent: Saturday, November 02, 2002 7:35 PM
Subject: [APML] Speeding up film with cold weather


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

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