- Front projection effect
A front projection effect is an in-camera
visual effects process infilm production for combining foreground performance with pre-filmed background footage.Description
In contrast to rear projection, in front projection the background image is projected on to both the performer and the background screen. This is achieved by having a screen made of
Scotchlite , a product of the3M company that is also used to make screens formovie theatre s. Scotchlite is made from millions ofglass beads cut in half and affixed to the surface of the cloth. These glass beads reflect light back only in the direction in which it came, far more efficiently than any common surface. In fact, Scotchlite is 100 times more reflective than the human body.The actor (or subject) performs in front of the reflective screen with a
movie camera pointing straight at him. In front of the camera is aone-way mirror angled at 45 degrees. At 90 degrees to the camera is aprojector which casts a faint image of the background on to the one-way mirror which reflects the image onto the performer and the screen; the image is too faint to appear on the actor but shows up clearly on the screen. In this way, the actor becomes his ownmatte . The combined image is transmitted through the one-way mirror and recorded by the camera.The technology needed for front projection was available since the invention of Scotchlite in the 1940s, but apart from some minor technical experiments in 1949, the process would not be used for feature films until 1966, during the filming of "". The actors in
ape suits were filmed on a stage atElstree and combined with footage ofAfrica . (The effect is revealed in the glowingcheetah 's eyes reflecting back the light.)Dennis Muren utilized a very similar solution for his 1967 debut film " Equinox", although Muren's technique didn't employ Scotchlite. Two British films released in 1969, "On Her Majesty's Secret Service " and "The Assassination Bureau ", used the technique.Front projection was invented by William F. Jenkins, better known to readers of
science fiction by hisnom de plume asMurray Leinster . Jenkins (Leinster) gives an account of the genesis and development of his invention in the November 1967 issue ofAnalog Science Fact & Fiction magazine.Zoptics
Front projection was chosen as the main method for shooting
Christopher Reeve 's flying scenes in "Superman". However, they still faced the problem of having Reeve actually fly in front of the camera. Yugoslav effects wizardZoran Perisic devised a new refinement to front projection that involved placing azoom lens on both themovie camera and theprojector . These zoom lenses were synched bycomputer so as the camera zooms in, the projector zooms out, or vice versa. The background grows smaller and the actor grows bigger; thusSuperman flies towards the camera. Perisic called this technique Zoptics. The process was also used in two of theSuperman sequels (but not used in the fourth movie due to budget constraints), "" and Perisic's sole film as director, "Sky Bandits " (also known as "Gunbus ".)IntroVision
In Front projection, light from the projector that travels through the
one-way mirror and is not reflected towards the scene is “soaked up” by black velvet. In IntroVision, the black velvet is replaced by another Scotchlite screen that reflects the image back towards another Scotchlight screen placed before the performer. Thus, the same image appears from two different sources and lands on two different screens creating a “3D” effectFact|date=May 2007. IntroVision was first used in "Outland" to combine starSean Connery with models of the Io mining colony. It was also used in "Under Siege ", "Army of Darkness " and "The Fugitive", where it seemed to placeHarrison Ford on top of a model bus that was then rammed by a model train.Front projection phased out
Front projection had several advantages over its main rival
bluescreen . It didn't have the thick black outlines that sometimes appear onbluescreen films. It was less time consuming - and therefore less expensive - than the long process of optically separating and combining the background and foreground images using anoptical printer . It allowed the director (if not necessarily the actors) to see the background and call out necessary adjustments (“Jump now, Harrison!”). And, especially with Zoptics, it was a more flexible system that allowed for more complex sequences that could be attempted at the time withbluescreen . However, advancements in digital compositing have rendered front projection obsolete. The last major blockbuster to extensively use front projection was theSylvester Stallone action thriller "Cliffhanger" from 1993.ee also
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Film production External links
* [http://www.visual-memory.co.uk/sk/2001a/page2.html Article with detailed method]
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