Pre-Production is the process of fixing some of the elements involved in a film, play, or other performance. There are three parts in a production: pre-production, production, and post-production. Pre-production ends when the planning ends and the content starts being produced.
In filmmaking and video production, pre-production formally begins once a project has been greenlit. At this stage, finalizing preparations for production go into effect. Financing will generally be confirmed and many of the key elements such as principal cast members, director and cinematographer are set. By the end of pre-production, the screenplay is usually finalized and satisfactory to all the financiers and other stakeholders.
During pre-production, the script is broken down into individual scenes storyboards and all the locations, props, cast members, costumes, special effects and visual effects are identified. An extremely detailed schedule is produced and arrangements are made for the necessary elements to be available to the film-makers at the appropriate times. Sets are constructed, the crew is hired, financial arrangements are put in place and a start date for the beginning of principal photography is set. At some point in pre-production there will be a read-through of the script which is usually attended by all cast members with speaking parts, the director, all heads of departments, financiers, producers, and publicists.
Even though the writer may still be working on it, the screenplay is generally page-locked and scene-numbered at the beginning of pre-production to avoid confusion. This means that even though additions and deletions may still be made, any particular scene will always fall on the same page and have the same scene number.