I got to see Robot Monster in 3D on a big screen at the Egyptian Theater in Hollywood at a 3D film festival. 3D back in the 50s was way better than it got a reputation for. The problem was that it was more work for the projectionists so often it wasn't shown very well. In those days film breakage happened pretty often but with 3D movies you had to replace messed up frames with "slugs" (empty frames) or the left and right eye would be out of sync. Also the feature length 3D movies had to have an intermission because it was using both projectors at the same time so required swapping reels in the middle of the movie rather than being able to just do a synchronized switch between projectors in the middle of the film.
I got to see Robot Monster in 3D on a big screen at the Egyptian Theater in Hollywood at a 3D film festival. 3D back in the 50s was way better than it got a reputation for. The problem was that it was more work for the projectionists so often it wasn't shown very well. In those days film breakage happened pretty often but with 3D movies you had to replace messed up frames with "slugs" (empty frames) or the left and right eye would be out of sync. Also the feature length 3D movies had to have an intermission because it was using both projectors at the same time so required swapping reels in the middle of the movie rather than being able to just do a synchronized switch between projectors in the middle of the film.
Great info!