Definition:
The cameras have stopped rolling. The work is not over. Post-production is everything that happens after principal photography ends: editing, visual effects, sound design, colour grading, music, and the final delivery of the finished film. It is the phase where a collection of raw footage becomes the thing audiences actually watch.
What It Means in Movies:
Post-production is where a film becomes itself. The editor assembles the cut. The VFX team builds the digital elements. Sound designers create the sonic world. Composers score it. Colorists grade the image. On a major feature, post-production involves hundreds of people across dozens of departments, all working toward a locked cut that can be delivered to distribution.
Why It Matters:
Post-production is where films are saved and where they are lost. Mad Max: Fury Road was shot largely as a practical, on-location production. George Miller and his team then spent years in post refining the edit, grading the image, and building the sound design that made it one of the most viscerally complete action films ever made. The shoot was not the film. The post was.
Example:
A major VFX feature finishes principal photography with thousands of raw shots, hours of location sound, hundreds of visual effects plates, and no finished film. Post-production takes all of that and, over the course of a year or more, turns it into something with a beginning, a middle, and an end.