In article , l41695@alfa.ist.utl.pt says...

> Could someone please tell me if I need to do some exposure
>correction when using B&W filters (such as red or orange) with a
>spot-metering camera.If not,any ideas how I managed to overexpose 3
>films? When all camera settings where right...

Hmmm, sure you didn't mean "underexpose"....?
Most TTL camera meters (and other meters) read strong colors
differently from the way the film records them, and underexpose
in the red end (my Nikon meters need to be + compensated 1/2 stop
for dark yellow, 1 stop for orange, and 1.5 stops for red filters,
contrary to what the manuals say [but, then, they also tell you
to focus at the long end of the zoom lens, then zoom back for the photo.....]).
Hope This Helps