Recently whilst in Florence, Italy for Pitti Uomo 94 I attended a Black Tie event at the Palazzo Corsini.
I wore a made to measure dinner suit from Tolley Savile Row here in Melbourne, Australia. The design I chose was single-breasted, large shawl lapels and plain pleated black trousers.
Now there are many die-hard rule followers when it comes to black tie and how a dinner suit/tuxedo should look and fit. Me, personally, not so much and I think this is where personal style plays a huge part in individualising a look.
Traditionally a black tie suit was classed as a leisure suit, this doesn't mean that it wasn't formal, it means it wasn't part of the military dress code thus it was for leisure and also ventless.
Military "suits" and jackets had a single vent as to be worn whilst riding a horse.
The suit style itself as the "rules" state can be single or double-breasted, shawl or peak grosgrain silk lapels, buttons, pockets and trouser outer seam, a cummerbund or vest, always a white band or wingtip collared shirt and patent black pumps.
Of course, nowadays there are slight variations to this dress code. Semi-spread collared stud-less or uncovered buttons, unpleated bibs, navy instead of black fabric, contrasting jackets, patent black oxfords or loafers and no vest or cummerbund.
Another change to modern day black tie would be the adding of double vents to the jackets.
Due to body profiles changing, if one wore the traditional ventless jacket they might look like a sack or it would leave bunched up fabric at the small of the back.
This is due to more athletic builds (wider shoulders, small waists and prominent seats), so a double vent can taper the waistline whilst still sitting clean over the seat.
So whether you have a black tie event or are wearing one for a wedding, think about what you want out of a tuxedo or dinner suit and choose right for your body profile.