Re: Color Mixing (Pigment) question

[John Denker <jsd@AV8N.COM>]

Bernard Cleyet wrote:
> this is the argument of the pointillists and impressionists.  [pure
> colour splotches instead of mixing on the pallet mixed by the eye, a
> more brilliant result]

More brilliant than what?

An arrangement of pure green paint splotches intermixed
with pure blue paint splotches cannot possibly be more
brilliant than covering the same area with an ordinary
bright cyan paint.  OTBE (other things being equal) you
would expect it to be roughly half as bright.

Think about the physics:  There is roughly a 50% chance
that a given incident blue photon will land on a green
splotch and be absorbed.  Similarly there is roughly a
50% chance that a given incident green photon will land
on a blue splotch and be absorbed.  A solid area of
ordinary bright cyan paint will be much less likely to
absorb either one of those photons.

I'm simplifying things somewhat.  Smart-alecks can conjure
up pathological counterexamples.  But what I'm saying is
a good approximation under normal natural conditions.