Three Fortnights
This is how long it takes to make the average movie, or so it would seem. Since time is money, it sounds appealing to tell a film studio executive that filming will only take a month and a half. Alternatively, you could be vague by saying that filming will take more than a month but not as much as two months. The only person who I can think of that actually benefited from six weeks of filming is Steven Spielberg when he made his directorial debut: Duel (1971). However, his movie had an extremely simple premise than other movies which I’m thinking of.
Although it only took 10 days for Ridley Scott to have Christopher Plummer reshoot Kevin Spacey’s scenes in All the Money in the World (2017), Ridley was aware of six weeks being the standard number as he told The Denver Post in December 2017: “Usually when I finish a film, if I have to do pick-ups I’ll do hand-shoots or close shots, which aren’t too expensive. There isn’t a whole unit standing there. But I’ve never experienced six weeks of reshoots. Maybe if the planning was wrong or the script was wrong or something, but it’s actually never happened.”
Alien 3 (1991) needed six weeks of reshoots as did Monster Hunt (2015), Rogue One: A Star Wars Story (2016), Justice League (2017) and Doctor Strange in the Multiverse of Madness (2022). Then you have films where a decision was made to reshoot after six weeks of filming: Enemy Mine (1985), Back to the Future (1985), Predator (1987), North Shore (1987) and Juno (2007).
Generally, six weeks is the barometer by which you are expected to do something in the world of films e.g. David Ayer was given 6 weeks to write the screenplay for Suicide Squad, Patrick Lussier was supposed to edit Wes Craven’s Cursed for 6 weeks in the summer of 2003, James Horner was promised that he would be given 6 weeks to compose the score of Aliens, and a dozen CGI artists had 6 weeks to complete 42 shots for Twilight: Breaking Dawn - Part One.