Color Filter with B&W Film

I'm wondering if my KB15 Blue filter would help increasing the impression of fog and soften the image (I don't have a

47). Thanks.

I've never used a blue, so I don't know - but I wanted to suggest you might get more help in the B&W forum. :-)

You could reasonably expect it to do the opposite of red - lighten the sky and shadows. I don't know about fog - blue is not a filter that I have found particularly helpful. But I see where you are coming from, if infrared penetrates fog then blue would do the opposite. Sometimes you have to do the experiment yourself.