The telecinema is a system making it possible to transfer an element film (silver film) on support usable in post production and diffusion television (video electronic image).
The different frequencies of run cause difficulty at the same time for the transfer of the image and that of the sound: 24 images/second for film and 25 images/second for television. The beginning of television, an adjustable obturator video camera combined with an obturator projector and variable speed could ensure a transfer of film carried to 25 images/second with a slightly accelerated sound.
By extension, the term indicates the treatment making it possible to adapt a film sequence to the selected numerical format. This treatment is based on the addition of complementary screens on the still image, process which makes it possible to transfer a film on silver film (8mm, Super 8, Format 16 mm, 35mm,…) towards a video support.
The apparatuses of telecinema are Projecteur S which project the image directly in a video camera connected to a Magnétoscope, which guarantees an optimal quality of transfer (not of parasitic light, not of loss of light).
Telecinema amateur
The silver film recovery, often one of the alternatives of the 8 mm, can be done with a material simple, available at the amateur.It is necessary:
- a projector, preferably at speed variable
- a camera, preferably numerical
- a screen translucent with mirror or opaque
Favors and disadvantages of a translucent screen
- With this assembly, it is easy to obtain an image without deformation, because the camera is placed opposite the axis of the projector.
- the grain of the screen can be seen whether it is not very fine and the rather large screen
- the white tends to be saturated
Favors and disadvantages of an opaque screen
- more easily available (a sheet of paper nongranulous white, like photo paper for printer, is enough)
- Problèmes of parallax and deformation, even of development.
- Reflections
Scanner with films
The best results are obtained with scanners with films: disappearance of the optical defects, so much of the projector than of camera (Curve of field, Ornamentation with vignettes, etc), perfect synchronism of the captured images, edges Nets, etcUnfortunately, this type of material is not available for the general public, and captures it of a relatively long film requires much labor.
Telecinema and format of image
One of the difficulties to which must face the operator during a transfer by telecinema is the adaptation of the proportions of original film on television if the proportions of image are not the same ones. For example, traditional television has a format of image of 4/3, either an image 1,33 times broader than high, or of 16/9, or an image 1,78 times broader than high, whereas the formats of cinema have another report/ratio in general (the image is often broader, with typically a ratio of 1,37,1,66,1,85 or 2,35).
See also: Format of projection
Here various methods used:
- one adapts the image horizontally, and one leaves black bands in top and bottom of the screen: there is a wasting of the surface of the screen, but one respects the integrity of the image and the artistic choice of the realizer;
- one adapts the image to the vertical of the screen, and one crosses what overflows horizontally: all the screen is used, but there is a loss of information on the edges;
- one does not adapt the image completely vertically, and one lets it a little overflow horizontally: these is a compromise which allows less wasting of the screen, and less loss of information;
- one compresses the image slightly horizontally (anamorphosis), which gives a light deformation of the image.
It is noted that none of these processes is perfect. The choice of the technique can depend on the material available, of the practices of the public or that of the technicians.
See also: Format of projection#Vidéo and television
See too
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Kinescopage : process reverses
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