Final answer:
Post-production of a film starts after the production phase is complete, involving editing and adding special effects to create the final version of the film.
Step-by-step explanation:
Post-production of a film can begin when the production phase is completed. This is the stage where the film director takes the helm behind closed doors, going through the takes and selecting the best ones to piece together the film according to his/her/their vision. The process involves editing, adding special effects such as music and computerized backgrounds, and all the final touches before the film is considered complete.
It is a detailed and intricate step where the variables of filmmaking, like non-chronological shooting and various technological tools like CGI, are creatively managed to finalize the project. Post-production is crucial as most of the creative decisions made during this phase significantly affect the final outcome of the film, way beyond the initial performance delivered by the actors on set.