Any thoughts on blue filters in black and white photography?

Using panchromatic film the colour of a filter will knock out or subdue it's own colour in the photograph,so a blue sky will turn whiter with a blue filter but red the opposing colour will darken it. Orange filters were used to lighten antique furniture, giving more detail to the grain, but I have not heard of the use of blue filters in portraiture. Of course the end results in digital photography would probably be different from using panchromatic film.