4 film survey requires 2 anterior occlusal and 2 bitewing radiographs.​ 8 film survey requires 4 posterior, 2 anterior occlusal and 2 bitewing radiographs.​ 12 film survey requires 4 IOPAs for posterior teeth, 4 canine IOPAs, 2 incisor IOPAs and 2 bitewing radiographs.​ 16 film survey requires 4 permanent molar radiographs additional to the 12 film survey.​Ref: Principles and practice of Pedodontics by Arathi Rao