Explanation of rear projection shots in old films?

[Phillyrich]

Is there anywhere on the web a good explanation of how rear projection shots were achieved with the blending into
live action in the foreground? This seemed to work better in the 1930s and 40's films--and the illusion working a lot
better--I think-- in black and white. Fifties rear projection often seemed, to my eyes, inferior. Was it the shooting
demands of color, finer film grain, the old masters retiring, or the labs less skilled. I wonder why?

[Marr&Colton]

It was quite interesting how process shots were done back then---an image projected through a translucent screen behind the actors. The process projector's shutter had to be interlocked with the camera shooting the scene so the process image didn't cut in and out as the shutters opened and closed.

Not all process photography was that slick---for those of us who remember Hal Roach's 1933-34 work with Laurel & Hardy and others. A lot had to do with whether the grain of the rear projected image was fine enough. Later on studios perfected the process.

[Ray Faiola]

Here's a still of Stan and Babe in front of the process screen in WAY OUT WEST. The close-up shots in this sequence were much more successful as far as the rear-screen projection was concerned.

[aldiboronti]

I always think of Marnie when pprocess shots come up. That ship at the end of the street doesn't look realistic at all.



But apparently that's the way Hitch wanted it.

Other scenes that also appear fake, such as the painted backdrop of a giant ship that’s moored at the end of Marnie’s childhood home, seem to have been more intentional. The perspective and lighting were off, and though his crew implored him to reshoot the scenes in which it appears, Hitchcock was adamant to let it remain as is. Quoting matte artist Albert Whitlock and others, Moral concluded that he “wanted this looming image because it was such an important memory from his childhood.”

http://www.alfredhitchcockgeek.com/2013 ... k-and.html