Some CS3 Filters Not Working

Working on a simple 8-bit RGB image in the Filter Gallery, I find that a number of them (bas relief, charcoal, graphic pen, and a few others) give an all black preview. I have tried different zoom levels and mucked about with the settings on each, but they just don't seem to work at all. Others work fine on the same image. I restarted CS3 and also tried a different image, but the result was the same. Working on an XP-Pro machine with 3GB RAM.

Any suggestions?

Thx

Have you tried pressing "D" to get the default colours in the Toolbox?

Thanks, John. Yep, that was it...both foreground and background were black. I love it when the problem turns out to be my stupidity, not a bug.

Cheers,
-R.

:)