I’m trying to recall if Disney’s The Parent Trap (’61) was the first film in which an actor played identical twins who sometimes appeared in the same frame. I’d like to find an article that explains the mid 20th Century technology that allowed for this, and how it differed from the prevailing method[s] used today.
Twin flicks seemed to accelerate (emphasis on the “s” word) after David Cronenberg‘s Dead Ringers (’88). Since then we’ve seen a shitload. My 21st Century favorites, hands down, are Armie Hammer‘s Winklevoss twins in The Social Network.