When MGM signed contracts with Stanley Kubrick, the studio originally expected 2001: A Space Odyssey to be ready for Christmas 1966, but that was soon understood to be unrealistic. A big opening in 70mm Cinerama theaters in April 1967 was the new goal, followed by wider release to mainstream theaters later that year. Towards the end of 1966, Kubrick finally showed a half-hour of clips of the film’s most visually impressive moments to Robert O’Brien, MGM’s CEO, as well as a handful of other MGM executives. They were relieved and reassured. The spaceships, the zero-gravity scenes, and details of the future were the most realistic ever made. As the year ended, MGM already knew they had a spectacular-looking space picture on the way. Crucially, though, they still didn’t really understand what kind of space picture they’d be getting.

To an unusual degree, many of the distinctive things about 2001 we’ve known for more than half a century weren’t yet created during principal production, when the actors were on the set. They came along later, in the laboratories and editing rooms, in 1967.

Kubrick’s message to the studio was, look how close to perfection we’ve come; don’t force me to rush the completion of these elaborate visual effects. Optical and other laboratory effects were being made to unprecedented levels of quality, and this was taking time. Plus, like any film, 2001 still needed to be edited, dialog dubbed, foley (sound effects) tracks done, and final music composed and mixed. Even vastly less elaborate films took a couple of months. With the complexity of 2001’s lab work, it’s understandable that this would push things later. In other words, he couldn’t make an April deadline.