The Justice League movies will be a huge step for DC Comics and Warner Brothers. It will be a huge step for super hero films in general. It will also be a huge undertaking for the production team.
According the the DC Extended Universe costume designer, Michael Wilkinson, the Justice League movie will take a year.
"I just started preparation on Justice League," Wilkinson explained during a panel at CCPX in Brazil. "We’re shooting the film in London. I’m gonna be be there for a year. 6 months of prepping, 6 months of shooting. We have all sorts of fantastic characters we’re bringing to life. All sorts of interesting universes. We’re looking forward to doing a whole new Justice League for the 21st century."
The 21st century also means that post-production on the Justice League film will be unimaginably lengthy, possibly taking the same amount of time as pre- and production, if not longer.
This should be an indication that both Part One and Part Two of the Justice League films, slated for 2017 and 2019, respectively, will film back to back as one continuous production, although an Aquaman movie is slated between the two in 2018 and Shazam arrives before Part Two in 2019.
Justice League: Part One hits theaters November 17, 2017.