The colour of the bow tie is not irrelevant--one should indeed wear a black bow tie with a black dinner jacket (a.k.a. tuxedo), black trousers and a white shirt in order to conform to 'black tie' dress rules. It's called black tie for a reason, and you don't want to look tacky, now, do you?

Dinner jackets really shouldn't be white, unless you are in the tropics.

Black tie should not be worn during the day, and should certainly not be worn to a formal wedding or funeral in Britain where Morning Dress is more appropriate. Otherwise, wear a lounge suit.

The women's equivalent of black tie is a cocktail dress, or a long dress, but not an off-the-shoulder number.

Black tie is not as formal as white tie.