I don't know if Kazan did that to make it look distinctive, or they didn't have enough money for rear projection or whatever.
The side and rear projections are clearly preserved in the Protostephanus holotype.
The image may be projected onto a translucent "rear projection" screen.
Backgrounds for the rear projection were filmed on the streets of New York.
He made several improvements on the matte shot to apply it to motion picture, and was the first director to use rear projection in cinema.
However, front and rear projection have some substantial differences.
However, rear projection has been a far more common technique.
For musicians sitting behind the screen the rear projection was particularly confusing.
Payne hit upon the idea of rear projection; projecting an image through a screen rather than on it.
Many of the film's outdoor scenes are shot against rear projections, which are quite noticeable.