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.