Split screen is "[a] visual composition in which the frame is divided into two separate images not superimposed over one another."4
The effect is achieved by blocking out part of the frame, then exposing the film. A second image is then photographed into the matted out areas. For Beast, Harryhausen placed his model on a platform in front of a rear-projection live-action scene, then matted out the platform. The rear projection advanced slowly as the monster was animated. He then reversed the negative and "filled in" the areas that had been masked. His carnosaur thus strolls those sidewalks of New York before, behind and amid buildings, cars and pedestrians.1
It was this film that earned Harryhausen his reputation as the man to see for low-budget, high quality special effects. However, Harryhausen still had more and even better work to do. When the cost of filming in Hollywood became prohibitive, he and producer Charles Schneer moved their operations to Britain. The Schneer/Harryhausen team was responsible for most of Harryhausen's most memorable films over the next seventeen years.
In Britain Harryhausen discovered the sodium-backing or "sodium vapor traveling matte" process, which allows images to be sent to two different lengths of film using a prism.
"A yellow screen is lit by sodium vapor lamps and the characters before it by incandescent lamps. A beam-splitting prism in the camera sends the yellow light from the backing around the characters to one of the films so that a negative is formed, with the background opaque and foreground clear..."4
A male matte (a matte blocks light from reaching the film) is then made in which the performers appear but the background is clear.
At the same time, the light reflected by the performers is sent to the second film, one insensitive to the yellow light. This creates a self-matting positive on which the background is opaque
The original film of the background and the male matte from the first film are then run through an optical printer, creating a negative into which the foreground (self-matted) positive can be inserted via another run through the printer. Though it has some limitations, the process creates mattes in a single exposure, compared to the as many as ten required by the standard blue-screen method.1, 4
But perhaps the scene that will ever represent consummate Harryhausen is found in a film based on Greek mythology he and Schneer made in 1963. The battle between Jason's crew and the army of skeletons guarding the Golden Fleece is a masterpiece of composition and animation and of the process that George Schneer had dubbed Dynamation during their work together on The Seventh Voyage of Sinbad.
 |
 |
 |
 |
 |
