Re: Is this the real earth?

Chris L Peterson wrote:

OK, but it doesn't make sense to call them "primaries,"

It does to the extent that neither actual sensors nor displays use
anything close to "primaries" in the rigorous sense that color theory
normally uses.

At that point, you were talking about an infinity of non-monochromatic
triplets, without any constraint on the relative intensities or the
shapes of the passbands. I don't know how to talk sensibly about that.

"Primaries" implies that I can draw inferences about them from color
theory. This works pretty well with sensors and displays. They behave
more or less in accordance with color theory--their sensitivities or
outputs are *as if* they were using monochromatic primaries. (And in
fact the narrowness of their response/output is often regarded as a
figure of merit.)

John mentioned Edwin Land's discovery that red and white projectors,
projecting grayscale images taken with narrow red and green filters,
produce apparently full-color images. I wouldn't use "primary" to
describe red and white in this case, because it leads to confusion.
Color-theoretical primaries can't really explain what happens, and
white is no kind of primary in any case.

I'm still not clear on where the experimental results you described
would fit. You've said your light sources matched the passbands of the
cones at one point, but at another that they were "narrow."

Of course, there's also the fact that the filter labeled "orange" on
Rosetta is actually what most people would consider "red".

Yes, there's that.

- Ernie http://home.comcast.net/~erniew
.

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