 The scene where the Demonic entity leaves Father Karres was originally done  by filming Jason Miller in possession makeup, then stopping the camera and  shooting him again with the makeup removed. This creates a noticible jump in  Father Karresss position as he is unpossessed. The 25th anniversary video  releases of "The Exorcist" smooth over the jumpy transition with a subtle  computer morph effect. This updated effect may have also been in the the  prints used for the 75th Anniversary Warner Brothers film festivals