What it is…
Double Exposure is the technique of exposing the same photographic frame or strip of film twice to light in order to superimpose one composition over the other. Depending on the type of superimposition (uniform/unbalanced) aimed at, lighting and exposure parameters could be altered when running the shot strip in the camera for the second time.
Why it is special...
The first of the two things that make the Double Exposure special is that it is a technique that is uniquely tied to the medium of celluloid. It requires that the chemical compound on a photographic negative be acted upon by light two or more times. Further, it is a cinematographic device that is at the foundation of the idea of the filmmaker as a magician.
When it is deployed...
With the proliferation of digital filmmaking practice as well as the extensive use of computer-generated imagery, the employment of Double Exposure has been almost totally eliminated. The choice between manufacturing trick images with the click of a mouse and carefully handling cumbersome film footage appears to be an easy one.
Where to find it...
In an iconic image from Dziga Vertov's Man With A Movie Camera (1924), the director superimposes the image of a camera lens over that of an eye. Vertov's use of the Double Dissolve is profound and striking in not only how it emphatically announces the merging of the camera's mechanical ‘eye' with that of a human, but in also that it produces the association without an Intellectual Montage.
How it is used…
Double Roles
To show two roles by the same actor in a single shot, the actor would play the first role and the scene would be shot with part of the film roll left unexposed. The scene would then be reshot with the actor playing the second role and, this time, with the hitherto covered part of the film strip exposed and the already-photographed side concealed.
Ghosts
Earliest practitioners of cinema – the silent film magicians – were quick to identify the use of Double Exposure to illustrate supernatural events and beings. The “ghost” to be photographed is rerecorded on a shot strip of film with a lower intensity to indicate an ethereal quality. They also used the technique in dissolves and montages where transitions have to be smooth.
