RolandL
Senior HTF Member
The London Casino was not a purpose built Cinerama theatre and was totally different from the Loews and Warners in NYC. There was no stage and no proscenium at the NY theatres. And unless someone shows me a photo demonstrating otherwise, I will continue to maintain that the screen was floor to ceiling and wall to wall.
The Loews Astor Plaza (1974-2004) was also built for Cinerama, but no Cinerama film ever played there. While there was no stage or proscenium there either, there was some masking and/or side or top curtains.
I know that for "This Is Cinerama" it opens with a single smaller 35mm image that had masking, but I really think that's besides the point.
The theatres that were built for Cinerama and some others that were converted did have floor to ceiling and wall-to-wall screens but, they did have masking. Below is a picture of the screen at the Denver Indian Hills Cinerama theatre. It is masked at the top and bottom for 1.85.
70mm Cinerama theatres had similar masking as D-150 theatres (see masking for various AR below).