Digital BW, The Print

Peter writes:

> That's what you SAY, but you haven't provided a
> specific example.

That's what the paragraph you backquoted was:

AA> Measure the spectral distribution of a scene (with a
AA> spectrometer, for example).  Then take a picture of
AA> that scene, in color (digital or film).  Now try to reconstruct
AA> the original spectral distribution curve using only
AA> the three data points provided by the RGB values in
AA> the color image.  You won't be able to do it, and you'll
AA> discover very quickly just how much information is gone.

See?

> We've repeatedly asked you to give us objective
> support for what you're saying ...

Who is "we"?  As far as I can tell, you are speaking only for yourself.
Several people here understand what I'm saying, even if you do not.  Perhaps
they can explain it better than I can, as I've given many different examples
and I seem to be making no progress.

> ... but all you offer is gedanken experiments and
> hypothetical situations.

Just like Einstein.

> If what you're saying is true you ought to
> be able to provide concrete evidence of it.

If you understand what I'm saying, you have all the evidence you need on
that basis alone.  Kind of like algebra, as opposed to arithmetic.

> Remember, your EYE doesn't reconstruct the spectral
> distribution of a scene either because it also
> relies on just 3 overlapping photopigments.

It doesn't have to.  It doesn't perform any conversions to other
colorspaces.

If you think about color blindness (specifically, the anomalous
trichromacies, not achromatopsia or deuteranopia or anything like that),
that might help to understand the difficulties involved.

> If what you're saying is true it ought to be a
> piece of cake to identify a color that comes out
> with a noticably different density compared to some
> reference color when scanned from black and white
> versus color film.

No, that does not follow.