Saturday night at the movies

[wa2ise]

Another way of feeding film programs into video was the use of "flying spot scanners". A frame of film is in darkness except for an image of a bright spot of white light projected onto the film. The spot is raster scanned over the film. Behind the film are 3 photomultiplier tubes, one with a green filter, another red filter and the third a blue filter. The amplified outputs of these tubes look like RGB video, which is then converted to composite NTSC video.