Rear Projection

Rear Projection

 

a special effects technique in which real objects, such as actors playing a scene, are filmed against a background that was shot earlier on motion picture or still film and that is projected onto a screen behind the objects being filmed. The rear-projection screen is a translucent screen on which an image is created by rays passing through it. A special projector, the rear projector, is placed behind the rear-projection screen, where it does not hinder the actors from performing in immediate proximity to the screen. This permits a sufficiently sharp composite picture to be obtained despite the shallow depth of field of the camera lens. Rear projection makes possible combinations of action and objects separated in space and time and, unlike certain other special effects techniques, permits the actor to see the background image during the filming, which is very important for coordinating the actor’s speech and actions with the events projected on the rear screen.

The rear-projection screen may fill the entire frame or only part of the frame, as when a landscape is shown outside a window or open door. The background image on the rear screen may be still or moving. For still backgrounds, dirsquoitive projectors with a powerful, water-cooled light source are used. Moving images are projected using low-noise projectors with a high light output. The projection is usually run at standard speed. In order for the timing of the exposure of the composite image to coincide with the timing of projection of the background image, the camera’s mechanism must operate synchronously and in phase with the rear projector’s mechanism.

Rear projection may be used in stop-motion photography, with irregular time intervals between the exposure of consecutive frames, as in the making of animated films. It is also used in films with a second subsequent projection (seePROCESS PHOTOGRAPHY), as well as in combination with other special effects techniques.

REFERENCES

Gorbachev, B. K. Tekhnika kombinirovannykh s”emok, 2nd ed. Moscow, 1961.
Kombinirovannye kinos”emki. Moscow, 1972.

A. A. SAKHAROV

References in periodicals archive ?
This state-of-the-art product redefines rear projection walls utilized in 24X7 control rooms as it provides a low total cost of ownership (TCO) benefits for existing operations.
Thanks to their small size and their capability to combine into virtually unlimited video wall shapes the rear projection display modules are ideally suited for creating projection surfaces in almost infinite configurations.
During the last three years, the cost of bulb replacement and maintenance has become null and void due to the recent integration of LED backlight solutions into rear projection displays.
For the showings, a very large screen is set up by the steps at the back of Worcester City Hall, with rear projection from a projector behind the screen.
TV market for CCFL LCDs rose to 65.3%, up from 64.6% in the second quarter, with the increase coming at the expense of other display technologies, including plasma, rear projection and cathode ray tube, iSuppli said.
Five different optional lenses allow for the XGA-resolution projector to be tailored for front or rear projection applications.
The main showcase to the event was a 6m x 6m Musion screen that hydraulically floated down from the trussing to sit at its desired position and was used to create a powerful and virtual 3D image/video in front of the main rear projection screen.
In the United States that accounts for 85 percent of Sony's rear projection TV sales, the company has begun to notify major retailers of the sales termination, they said.
SONY ELECTRONICS will expand its microdisplay rear projection television lineup to include a 50-inch and 60-inch screen model.
Annotated images may be simultaneously displayed on rear projection, plasma displays or traditional screens using LCD projectors.