Double exposure is the superimposition of two images, one over the other, which results from exposing the same film twice. This technique, which is not used as much today as in the past, is employed to create a ghost or a dissolve, or to make one character appear to be two. In the case of Buster Keaton’s The Playhouse (1921), multiple exposure is used to create the illusion of a series of Keatons playing in an orchestra.