Re: metamerism and metameric color - more
Re: metamerism and metameric color - more
- Subject: Re: metamerism and metameric color - more
- From: Igor Asselbergs <email@hidden>
- Date: Thu, 21 Jun 2001 11:47:31 +0200
>
> again we
>
> have to stick to the definition of metamerism ( two colors possesing the
>
> same trichromatic values but differ in the spectral distribution)
>
>
This cannot be a valid definition (with respect). Obviously, the two
>
objects *must* have different spectral distributions or they would
>
*always* look the same, so this part of the definition is merely stating
>
the obvious.
If you leave it out of the definition, what do you wind up with?:
'metamerism = two colors possesing the same trichromatic values.'
:-)
>
As for this fantastic "white point adaptation" postulated (or documented
>
- he obviously knows a lot more about it than I do)
I don't have a degree in this stuff, but I did work closely toghether with
someone who does. I also witnessed some quite interesting experiments
involving color constancy and I develop graphic software that takes these
effects into account.
But I'm not familiar with any research that would proof the the 'white apple
effect' actually exists. I'm merely reasoning from what I know of the
effects.
>
by Igor I have two
>
questions. First, why doesn't the entire red room look just as white as
>
the apple is supposed to. I have been in rooms, albeit not red rooms,
>
illuminated by red light (not in Amsterdam, BTW) often enough to know
>
that they don't look white to me. They look red (as in a dark room, for
>
instance).
I would think that if you're ONLY exposed to red light for a certain amount
of time, red light would become white. But any little amount of light (from
a small window, for example) that contains more then red wavelengts would
spoil the effect. Also if the amount of time isn't long enough you wouldn't
have time to adapt, it wouldn't work.
One time I encountered a related real-life situation. Walking up in the high
mountains in the snow, I was surprised by a thick fog. I couldn't tell the
difference between the white mountain and the white sky. So I was totally
blinded with eyes wide open. But when I turned my eyes to my body, the color
of my skin had turned almost fluorescent pink and my blue jacket almost
burned my eyes. It seems that somehow my viewing system crancked up the
saturation of all colours. Probably because my enviroment only contained
zero-saturated colours.
Amazing.
Igor Asselbergs