Digital BW, The Print

Anthony,

> It's very easy to demonstrate.  Take a picture in black and white using a
> narrow-band color filter.  Those are not difficult to find.  Then take a
> picture of the same scene in color without a filter.  Then try to convert
> the color image to B&W in a way that duplicates the same shades
> of gray you
> see in the B&W image taken with the filter.  You'll find that it cannot be
> done.

Who cares about that, but you?  I don't use colored filters for my B&W
images.  Ever.

You know, if this just doesn't work, then how come it DOES in fact work?  I
see B&W images made from color ALL the time, and they look VERY close to
"same" B&W images shot with B&W film...  So, how is it that thousands of
people already do what you claim impossible?

> The real-world relevance is self-evident to me and
> to several
> other people.

As it is to me too.  I can take a color image.  I can take a B&W image of
the same scene.  I can scan them both.  I can manipulate the color image
tonality such that it VERY closely matches the tonality from the scanned B&W
image.  I can do this manually, or I can do this programmatically, as I
believe it's a deterministic mapping.  As I said, thousands of people make
B&W images from RGB data every day.  Of course, some better than others.
But, as I said, if so many people are doing this so successfully, how can
you believe it's impossible?  I know, you'll argue the meaning of
"duplicate" and "successful" etc.

Austin