It is not surprising that the motion picture relies to a considerable extent on devices borrowed from the theatre. There are many superficial points of resemblance between the two arts. Films are shown in auditoriums which do not differ in any marked degree from other playhouses. Stage actors perform in films. Stage training is still regarded as a fairly satisfactory prerequisite for appearance before the camera. Actors, directors, and writers move from stage to screen with comparative ease and with what seems to be minor adjustments of their techniques and methods. It is often customary to draw a stage curtain back and forth to mark the beginning and end of the drama projected on the screen within the proscenium arch.