Re: Color of Mirror

From: Randy Poe (poespam-trap_at_yahoo.com)
Date: 09/23/04 

Date: 23 Sep 2004 13:45:18 -0700

timothy42b@aol.com (TimR) wrote in message news:<87af0be7.0409222226.74bdf57d@posting.google.com>...
> hhc314@yahoo.com (Harry Conover) wrote in message news:<7ce4e226.0409191225.4b0d2d87@posting.google.com>...
> >
> > Huh? I don't seen any logical connection between your two questions.
> >
> > On the other hand, if you reference a 3-color chromaticity diagram it
> > will become clear to you that 3-additive colors (such as those
> > available in a color TV or computer monitor) CANNOT reproduce all of
> > the natural natural color possibilities. For example, try to find
> > brown or olive on the chart of red, green and blue primaries.
> >
> > http://www.efg2.com/Lab/Graphics/Colors/Chromaticity.htm
> >
> > Note that this has absolutely nothing to do with mirrors and
> > reflection.
> >
> > Harry C.
>
> Harry,
> Thanks for the link, very interesting. I'll have to read it slowly.
>
> I told my kids our eyes had three types of sensors, red blue and
> green, and that is why they are the primary colors. Of course they
> told me I was wrong, the teacher says the primary colors are red
> yellow and blue. Huh? (this has been repeated with several other
> elementary school science issues, like glass flowing, how airplanes
> fly, etc. My kids won't let me read their science books anymore.)

You already got an answer on subtractive colors. Tell your kids
their computer and TV screens use red, green and blue phosphors
to create all the colors they see on the screen. It's all made
by mixing R, G and B light of different intensities.

>
> Anyway, that's my question with your statement. Even if brown or
> olive aren't on the chart, clearly we can see them with our
> red/green/blue eyes. So can't we make them on a computer monitor with
> red green and blue light?

Yep. It's not just the proportions but the intensities of the
primaries that give you different color appearances. Brown
is really very dim red (with shadings of the other two).
If you have an art program, see what happens when you use
a low intensity red with no green or blue.

Other dark shades are also made by using small amounts of
R, G and B. Light shades by using more. Equal amounts of
R, G and B give shades of gray.

             - Randy

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