Color corrector

Color grading is the process of altering and enhancing the color of a motion picture, video image, or still image electronically, photo-chemically or digitally. Color grading encompasses both color correction and the generation of artistic color effects. Whether for theatrical film, video distribution, or print, color grading is generally now performed digitally in a color suite. The earlier photo-chemical film process, known as color timing, was performed at a photographic laboratory.

The earliest film grading technique, known as colour timing, involved changing the duration of exposure processes during the film development process. Colour timing was largely used for colour correction, but could also be used for artistic purposes. Colour timing was specified in printer points. Since it could not be performed in real time, colour timing for film processing involved considerable skill in being able to predict correct exposures. For complex work, "wedges" were sometimes processed to aid the choice of the correct grading.

With the advent of television, broadcasters quickly realized the limitations of live television broadcasts and they turned to broadcasting feature films from release prints directly from a telecine. This was before 1956 when Ampex introduced the first Quadruplex videotape recorder (VTR) VRX-1000. Live television shows could also be recorded to film and aired at different times in different time zones by filming a video monitor. The heart of this system was the kinescope, a device for recording a television broadcast to film.

The early telecine hardware was the "film chain" for broadcasting from film and utilized a film projector connected to a video camera. As explained by Jay Holben in American Cinematographer Magazine, "The telecine didn't truly become a viable post-production tool until it was given the ability to perform colour correction on a video signal."

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