Celluloid-based photographic medium or — today — the finished motion picture work. On set, typically refers to the physical stock or its digital equivalent.
When you hear the word "film" on set, you have to infer from the context what is being discussed – this is what makes the term tricky. The gaffer asks you, "Which film do you need?" meaning the material in the camera. The producer says, "We're shooting a film," meaning the finished work. Historically, "film" was the celluloid strip itself, Kodak Vision3 50D or 200T – the thing you load into magazines. Today, with digital sensors and RAW recording, the physical material is gone, but the metaphor remains. You still think in terms of "films" – as if real celluloid were still running.
On set, you need to understand: film as material has concrete properties. Grain, color rendition, exposure latitude – these shape your lighting setup. Kodak stock reacts differently than Fujifilm. This was physically tangible before; today, you simulate it via LUTs and sensor characteristics. Film speed (ISO/ASA) determines your aperture and shutter speed. A 50D forced you to use more light than 200T; this wasn't abstract. With digital cameras, you sometimes forget this – you think you can push it infinitely. Wrong. The sensor architecture sets limits, just like celluloid grain.
Film as a work of art – this is the other dimension. The "film" is the finished object, editing, sound, color grading, DCP. Your work as a DoP culminates in this. In the past, this was a linear chain: shooting → development → editing → cinema. Today, it's more complex – you shoot digitally, grade in HDR, and deliver for cinema and streaming in parallel. Nevertheless, the end product is called a "film," even if no celluloid ever existed.
The practical distinction: In the call sheet and in communication with the producer, "film" is the material – "We still need 200 meters of 200T." In the pitch and with the audience, "film" is the completed work. As a DoP/cinematographer, you must be able to mentally separate both meanings. Your job is to expose and stage the material – whether chemical or digital – in such a way that a film is created in the end that holds up.