Perforation

The perforation of a film strip determines how the camera physically transports the film — and thus, what image quality and resolution are even possible. On set, you notice this immediately: 35mm film with standard perforation (4-hole) runs differently through the camera than 16mm with 1-hole perfs. The sprocket holes — these rectangular cutouts on the film edges — engage with the transport mechanism's sprockets and pull the film exactly frame by frame through the gate and shutter. The size, spacing, and type of these holes are not variable: they follow industry-standard dimensions, otherwise the film won't fit in any camera or projector in the world.

In practice, you primarily distinguish between standard perforation (four holes per frame on 35mm) and BH perforation (Bells & Howell, larger holes), which was reserved for older cameras. With 16mm, you work with 1-hole (Kodak Standard) or 2-hole perfs — this affects the usable image size. When switching to Super-16, the perfs become asymmetrical because one film edge is reserved for optical sound. These details sound technically dry, but they determine editing compatibility and projection. A 16mm film with the wrong perforation cannot be shown on standard 16mm projectors — and in a digital workflow, this becomes a real problem for raster recognition in the DCP master.

The precision of the perforation is also a quality control issue: worn transport sprockets damage the sprocket holes, scratches occur, and the film runs unevenly. That's why good focus pullers regularly check the perfs for wear. With archival material, you often see damaged or even missing holes — then it becomes critical during editing and transfer. Some digital intermediate houses have to restore old films beforehand to scan them at all. The perforation is therefore not just a means of transport, but also a physical testament to film history: it tells you on which camera and in which era this film was shot.