The speed with which film passes through a camera or projector : 70 mm sound film passes through at 112.5 feet per minute ; 35 mm silent film at 60 , and 35 mm sound film 90 feet per minute ; 16 mm silent film at 24 and 16 mm sound film at 36 feet per minute ; and regular 8 mm silent film at 12 and 8 mm sound film a 18 feet per minute.