Not sure if we had gone over this before but I just stumbled across this on in70mm.
2001" and the flat screen
Quote from a Douglas Trumbull interview in Cinefantastique June 1994:
"The film was shot in Super Panavision for projection on the curved Cinerama screen but the unique format wasn’t accounted for during the years of production. During the entire production, we never once viewed footage on a curved screen or in the format.
What would happen is we’d shoot in 65mm, but the lab would generate 35mm anamorphic prints for us to look at on a small flat screen. We never saw it in a Cinerama theatre. It wasn’t until the very, very end of photography, or maybe once during production, that I think Kubrick took a couple of 70mm prints and went down to a 70mm theatre to see how it looked. So, in a sense, the movie was not made with a curved screen in mind. In some of the Cinerama theatres there were a serious projection problem, because the projection booths were mounted up too high and you had a horrible sort of curved, keystoning effect: the titles would come out badly curved and it looked very distorted".