Re: AKICIF: Security cameras
- From: dbell@xxxxxxxxxxxxxxx ("David G. Bell")
- Date: Thu, 11 Sep 2008 11:55:18 +0100 (BST)
On Wednesday, in article
prd@xxxxxxxxxxxxxxxxxxxx "Paul Dormer" wrote:
In article <80lec4pmknidjlm2648ltqsb42qmau46u9@xxxxxxx>,
fairportfan@xxxxxxxxx (mike weber) wrote:
That's true even of film that's not at all sensitive to infrared.
(And since they have to do something special just to make it sensitive
to red light, *no* film is sensitive to infrared unless it's
specifically designed to be.)
Right. So you compensate for the differences in colour response in
the development process. (Or by tweaking the camera's white balance,
I remember back in the eighties a fried was taking some pictures of the
Prom concerts in the Albert Hall. Flash photography was banned (well, I
think all photography was banned, for copyright reasons, or something
like that, but the stewards tended to notice people using flash) so he
was using normal daylight film but with a filter that adjusted for
artificial light. What was odd was if you looked through the view finder,
how blue everything looked.
Yes, the human eye system is pretty good at adapting to the shifts in
the colour of lighting, though the way that dyes and coloring change
colour doesn't always match well.
What makes a photo look odd is that it is a small object in the field of
view. Get a really big photo which dominates the light-scape, and your
eyes will correct the result.
I've used those filters. They really lose a lot of light as well, which
isn't good indoors, becauase the lighting is alreader darker. Tungsten-
balanced slife film was also balanced for photographic lighting, which
ran the bulb filaments hotter than ordinary lightbulbs. So it reduced
the red cast, but didn't entirely eliminate it.
David G. Bell -- SF Fan, Filker, and Punslinger.
On the horizon, a carrier task force of the Salvation Navy was
turning into the wind, preparing to launch Zeppelins.
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