An Introduction to Backlight Compositing
Starlog #60 (July 1982)
Tron: by Dave Hutchinson.
To create the various color and light intensities of the various video warriors, cel painters create hold-out mattes by blacking out individual portions of the figure at a time. this example of the villainous Sark indicates a total of four hold-mattes, so designed for an equal number of camera passes. Each time a hold out matte is painted to black out certain portions of the figure, one or more other specific areas are clearly revealed for exposure, making graduations of light and color possible for the final electronic world character.
From left to right are: Sark, as shot during productionon a sound stage draped in black: the post production elements eye reveal, face reveal and circuitry reveal; and finally Sark as he appears in TRON. Such labor intensive post production involves 10 months, about 450 people and over 200,000 cels.
The Art of TRON
By Michael Bonifer
Chapter 8: Painting With Light.
#"TRON" is the first motion picture to use backlit, composite photography throughout to color characters and environments. "Painting with Light" is the term given to the teqnique developed by Richard Taylor, who pioneered its usage in the early 1970's in television commercials for Levi's and Seven-UP. Simply described, backlit photography requires that each frame of film be rephotographed against a light source. Colored filters over the camera lens and varied exposures give the characters and environments their hues while modulating the intensity of the glow. But the simplicity of the description belies the complexity of the practice.
The electronic world was originally photographed on 65 mm (the addition of the soundtrack makes the finished film 70 mm) black and white film, with actors in black and white costumes against black backgrounds. Each frame of film was blown up into several sixteen-by-twenty-inch transparencies- some to expose circuitry, others to expose costumes, fleshtones and eyes. These transparencies were placed, one at a time, over a light box and reshot with the appropriate color filter over the camera lens. Black hand- painted mattes were made to add background , either color comosited from gray-tone paintings or computer generated, to a scene. The photographic elements for compositing the colors in a frame were called an art package. The average art package contained eleven elements, but at times contained as many as thirty. In all, there were nearly 500,000 transparencies printed or painted for the film.