The front projection (also front projection is called) used to produce artificial backgrounds studio recordings, similar to the back-projection or the more modern blue screen technique . In contrast to rear projection, the background is not projected from behind but from the front onto a highly reflective screen.
The projector is set up at a 90 ° angle to the camera . The background image is then projected by the projector ( synchronized with the camera motor ) onto a semi-transparent mirror , which is attached at a 45 ° angle in front of the camera lens and through which the scene is filmed. This results in an exactly axial projection ("from the point of view of the camera"), i. H. the projected image has exactly the same remission as the object to be recorded to the camera.
With identical focal length settings of the lenses of the camera and projector, no shadows can be seen during the front projection, since the objects - mostly actors - cast shadows on them in front of the screen, but these cannot be perceived by the camera, as the object in the camera is exactly the same appears as large as the shadow behind it.
However, in contrast to rear projection, this also creates a disadvantageous effect at the same time: the projected images inevitably also appear on the structures in front of the projection surface and / or the people acting, on their clothing and - particularly annoying - on their faces.
Highly reflective canvases were developed to remedy this. These canvas or metal walls, coated with a specially shiny, very high silver grain, are real "light collectors", so that much less light intensity can be used for projection than for the guide lights of the objects in front. The so-called "Aufpro-Phenomenon" arises , a double effect in which
- Firstly, the images on the projection wall in the background do not look darker on the exposed (exposed) film image than the objects / people in the foreground and - despite the weaker projection light
- Secondly, the weaker projection images “thrown” onto the foreground objects through clever measures, such as a lighter cloakroom, matt make-up through the associated absorption (sometimes also through effect lighting, e.g. emphasized back, edge and side lights ), become so insignificant that they can in fact only be discovered through analytical observation; in a gripping storyline (plot) at this point they are then quasi "disappeared".
The disadvantages of this method, in addition to the resulting restrictions in setting the light, were above all a mobility of the camera / projector combination (tracking shots, zooms) that was not possible due to the complex, laborious handling of the equipment. However, especially with the demands of the emerging color film , the on-pro pictures were much more brilliant than the rear-pro pictures, where the background - reversed - through a screen (small, mostly only showing car windows or train windows) or through a very thin screen (sees always “muddy” and the projection lamp, which shines into the camera lens, comes out as a slightly lighter spot in the middle) that had to be projected through. With the "Aufpro" the light from the projection lamp does not shine into the optics and you can - through the use of the fine-grain projection walls - project sharp images onto much larger areas. Today, front projection is hardly used any more , due to the higher quality and simplicity of blue screen and compositing processes.
The best-known example of front projection is the 1968 created science fiction film " 2001: A Space Odyssey ," originated the input sequences of the beginnings of mankind exclusively in the studio with the help of front projection.