[Tig] color perception of lights

Martin Euredjian ecinema
Fri Oct 19 03:39:20 BST 2001


From: "Dominic Case" <dominic_case at atlab.com.au>

> I don't think Martin's explanation accounts for the the exaggeration of
> perveived colours that Rob describes. The graph of atmospheric absorbtions
> shows that most visible spectrum is transmitted quite well - as we know,
UV
...
> look upwards from the ground. But the same atmosphere would make _all_
> terrestrial light sources look more orange if that were the main effect.
...
> points of light, to be compared with other point sources of different
> illuminants. So we are better able to notice the difference.

You could be right.  I don't doubt it.

I think that published atmospheric absorbtion data accounts for some sort of
a "standard" atmosphere, an average, I'll assume clean atmosphere.  The
atmosphere over Los Angeles is nothing close to a clean and standard
atmosphere.  The first time I realized what we inhale every day was the
first time I sailed about twenty miles off the coast and looked back.  I saw
what I can only describe as a purplish/brownish bubble or dome over the
city.   I would guess that this smog bubble does something to surface lights
when viewed through it from a vantage point well above the top of the dome.
My guess is that the "additives" they have flowing over Rio (to go with
Rob's example) might just be different enough to make a difference.

Just a theory.

BTW, due to international pressure I refrained from using the word "stuff"
in this message.  :-)


-Martin Euredjian
eCinema Systems, Inc.
(661) 305-9320
ecinema at pacbell.net









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