In rec.photo.digital Mxsmanic wrote:
David Dyer-Bennet writes:

You're weird :-).

I like to record things as they are.

Seriously, using filters to control B&W tonal rendering is *extremely*
common among people doing B&W landscape photography, and other kinds for
that matter. Ansel Adams was famous for pushing the skies to really
dramatic low levels with a red filter.

They were not shooting things as they are.

You can't represent coloured things as they are in monochrome.

Suppose you were drawing a landscape with pen and ink wash. You will
draw a lot of black lines round the edges of things. But there are no
such black lines in a photographic image of the scene. That's just one
of many possible conventions for representing what you see. Now you
come to the deep blue sky with massed clouds varying from white to
gray. There is a striking colour contrast between sky and clouds. But
almost none in luminance between the darker clouds and the blue
sky. So how do you represent this in black and white? Lots of artists
would choose to darken the sky to represent the contrast.

Monochrome photographers who use red or orange filters to darken blue
skies are simply following the same representational convention to
represent what they see to be there.

--
Chris Malcolm