Well, had planned on using a much more colorful subject but, after my first shot it started to rain. So I went under an overhang and shot this scene. This shows hows subtle the filter usage can be in flat, overcast light.

First off, here's the scene in color, straight from camera. Shot with a Canon G2


These were shot with Tri-X and developed in Kentmere K110 dil. B

NO FILTER


YELLOW FILTER


GREEN


ORANGE


RED


LINEAR POLARIZER


The differences are subtle and may best be viewed as a SLIDESHOW.