Roy Lewallen wrote:

It's not very simple.

Except for monochromatic light sources like lasers, light of any color
contains multiple spectral lines. Sunlight or, for example, an
incandescent bulb or red hot electric stove element contains a
continuous spectrum, or effectively an infinite number of spectral lines
or "colors". So you can't duplicate these with any finite number of
spectral lines. The interesting thing is that with only three spectral
lines (pure monochromatic colors) you can produce light that *looks*
line nearly any color of light that's really made from many spectral
lines.

AHa! I was going to write about the emulation of color, but wasn't sure
if I'd just confuse things. But you've done a good job describing it, so
here we are.

So called "Lippmann" emulsions can do color correctly, but they work on
a wavefront basis instead of combining colors.(the individual particles
of silver are extremely small, so they can do that) A color Lippmann
image can be gorgeous, but they are really difficult to make, so are
more of a curiosity than anything else.


which is why they're common, but no choice can mimic all. I notice that
some color printers have more ink colors, which I assume allows an even
wider range.

That's a big part of it. Inkjets have some mechanical issues too, such
as the best looking colors might not last very long, or a good long
lasting color might be hard to squeeze through the little jets. SO we
get stuck with multiple color cartridges. But for the purposes at hand,
the color perception issue is the big one, and the others can be ignored.

- 73 de Mike N3LI -