P3D Re: filters for black and white photography

["William Carter, Ph.D." <wc@xxxxxxxxxxxx>]

At 12:31 PM 10/13/99 -0600, Linda Nygren inquired:
  >... my question is about what filters are useful for b & w and what each 
type does.

The easy answer is: think of the filter as a "band pass" filter; i.e., 
choose a red filter to darken a blue sky, or a blue filter to increase the 
dulling effect of haze. Your filter choice will lighten that particular 
color, and darken the complementary of that color.

Here's where I think it gets sticky; identifying the appropriate 
complementary. For instance, a good filter for taking head shots of WASPs 
would be green (complementary: magenta).

You also need to know what colors your film is most sensitive to. Is it 
pan, ortho, or what? That's a kind of 'built in' filter. I shoot in color, 
and filter when I make b&w prints. I like to keep my options open :-)