🚀 go-pugleaf

In article <162300002@uiucdcsb>, kadie@uiucdcsb.cs.uiuc.edu writes:
> 1) On TV's and computers screens, why is it RGB (red, green, blue)
> instead of RYB (red, yellow, blue) the primary colors?

Green, not yellow, is the primary color.  The three types of cones in our
eyes have peak sensitivities to red, green, and blue.  Red+green "add" to
appear "yellow", because yellow light stimulates both green and red cones
much more than blue cones. When you mix paints, you are using "subtraction",
which is more complicated. Yellow paint absorbs blue light well, green and
red less well.  Blue paint absorbs red and yellow well, green and violet
less well.  When you mix the paints, you get therefore get a paint which
absorbs red very well, yellow fairly well, blue fairly well, but green only
somewhat, so it appears green.

> 
> 2) Some light wave length produces the color green. A mixture of
> the wave lengths of blue and yellow also produces green.
Not true (see above).  Recasting the question, substituting "yellow" for
"green"...
> Even though these two greens are indistinguishable to our eyes, are there
> (could there be) instruments that distinguish them?

Yes. Absolutely.  They exist.


-- 
David Loewenstern                     Bangpath: {rutgers...}!moss!whuts!davel
The above are not my opinions. 
My lawyer has advised me not to tell you what my opinions really are.