How to avoid wearing help when filming actors facing the mirror in film and television dramas?

With the development of film technology, the use of special effects is becoming more and more common. More and more movies will be shot on green screens and then synthesized later. Its expressive techniques are more convenient and diverse, creating many surreal lens languages with both aesthetic feeling and fantasy color, such as the film Black Swan. The mirror is one of the important symbols in Black Swan, and Byakki Smoker's objects symbolize the dark side of the protagonist's heart, which is a metaphor for her gradual transformation into a black swan. When shooting scenes in the mirror, the photography team will adjust the shooting angle to avoid camera wear; Or use special effects to make scenes in the mirror, creating an extremely strange and creepy atmosphere. "There are mirrors everywhere in this movie. To complete the shooting, you must get a clean reflection scene. " DanSchrecker, director of visual effects, said that in order to show the "unsynchronization" between the protagonist and Byakki Smoker, the production team used the green screen to shoot the mirror reflection first, then the real scene, and then synthesized it with Nuke and After Effects.