The original plan was to have the circuit lines of the "good" programs glow yellow, and the "bad" programs would have blue circuit lines. At one point this was changed to where good programs are blue, and evil ones are red. Some of the original coloring remains, mostly in tank programs (Clu has yellow lines on his uniform, and all of Sark's tank commanders are pale green).But Flynn takes on this greenish tint after he crashes the reconizer and gets knocked out, shortly after he gets up he returns to the normal blue. This is also seen some shots in the original theatrical trailer, Master Control appears blue in one shot and in many shots of the main characters they appear yellow.
During the ENCOM exterior shooting (where the giant door was), there had been radioactive spillage near the shoot. Cindy Morgan even stepped in a contaminated area and had to have her shoes decontaminated.
The 'pulsing' flicker in some scenes in the computer world were the accidental result of a mix up during production. Each B&W 65mm frame of the film was printed on 20"x16" Kodalith high contrast film as high contrast positives which were then used to print as high contrast negatives. These positives and negatives were then colourised and used in the film. The Kodalith was produced by Kodak in the necessary size as a special order and the film boxes numbered in order of each batch produced so that there was a consistent film speed if used in order. However this was misunderstood by the Tron crew and they were used in any random order which resulted in some frames being brighter/darker than others and resulted in the flickers as the film speed varied. Once this was found out, the film was used in order of production to minimise the effect, but in the end the producers actually added in more flickers and 'zinger' sounds to represent the computer world glitching as Steven Lisberger described it. However he digitally removed them from the 2011 Blu-ray release as they were not in his original vision of the film and he believed they detracted from the quality.
TRON is also a debugging command in the BASIC programming language, meaning "TRace ON." However, Steven Lisberger, has stated in interviews that he took the name from the word "electronic," and did not know about the BASIC command until later.
At the time, computers could generate static images, but could not automatically put them into motion. Thus, the coordinates for each image, such as a lightcycle, had to be entered for each individual frame. It took 600 coordinates to get 4 seconds of film. Each of these coordinates was entered into the computer by hand by the filmmakers.
Composer Wendy Carlos' score for the film was unavailable on CD for many years due to the severe degradation of the original analogue master tapes. By the time of the film's 20th Anniversary, techniques had been developed which allowed the tapes to be temporarily restored to a playable condition for digital re-mastering.
The DVD commentary notes that there is almost no camera movement whatsoever in any of the shots of the electronic world with live-action characters in them. They brought in a camera and tripod with metal batwings attached, and literally nailed the camera to the floor; the camera was so locked off that "it wouldn't move even if hit by a car". The few shots with live-action characters which actually have camera movement (about a dozen shots in all) involve simple graphics or animation, such as one-color backlighting.
Many Disney animators refused to work on this movie because they feared that computers would put them out of business. In fact, 22 years later Disney closed its hand-drawn animation studio in favor of CGI animation. Hand-drawn animation was ultimately resumed at Disney at the behest of new creative director John Lasseter, also head of Pixar- ironically a computer animation company.
The ENCOM laser bay was real. It was actually the target bay for the twenty-beam SHIVA solid-state laser facility at the Lawrence Livermore National Laboratory. It was used for nuclear fusion research in the late seventies and early eighties, and was capable of delivering up to 28 trillion watts of power on target.
While computer animation was used in several scenes, the technology did not exist for a shot to contain both live actors and computer animation. Live-action shots were combined with hand-drawn animation. Strong editing, such as with the light cycle chase, created an apparently seamless blend of actors and computer animation.
The scenes in the computer world were produced using 'backlit' animation and computer generated imagery. The actors performances in the computer world were captured on B&W Kodak XX film using 65mm Super Panavision 70 cameras and each frame was printed on high contrast Kodalith sheet film as a positive and then subsequently a negative. These had coloured light shone through then onto colour film to produce the characteristic 'glowing' and required a separate exposure and film layer for each character detail, object etc which produced each frame in Tron when every layer was combined, with some having 16 layers or more. The CGI scenes were outputted from CRT's onto horizontally running 35mm Vistavision and these layers combined with those from the live action. In the 'real world', performances were captured on standard colour negative 65mm film and some were shot on anamorphic 35mm and 'blown up' to 65mm.
To inspire the actors, arcade games were placed on the production sets and could be played during downtime. Jeff Bridges apparently was the most adept at the games and found it hard to tear himself away from a game to shoot a scene.
The building featured as "Flynn's" is in reality the historic Hull Building at the Northwest corner of Washington Blvd and Watseka Ave in Culver City, CA. The street sign for Watseka Avenue can be seen when Lora and Alan step inside "Flynn's" to warn him about Dillinger. As of 2010, the location portrayed as "Flynn's" was occupied by a restaurant.
The programmer's cubicles at Encom were shot using the actual programmer's cubicles at The Walt Disney Company's Information Technology group. A matte painting was used to expand the area to a size more appropriate to a software company.
Co-writer Bonnie MacBird first studied computer programming with paper and pencil in the 1960s during junior high school. While attending Stanford she made punch cards for use on a PDP-11 minicomputer at night when students were allowed access, and played a rudimentary version of Pong with lights on the computer's control board. Before joining Steven Lisberger's company, MacBird worked as a mid-level story executive at Universal Studios where she tried unsuccessfully to get their story department to put their records in a database. It was MacBird's suggestion to Lisberger that they get computer pioneer Alan Kay as a consultant on the film they were developing. MacBird sent versions of the script via acoustic coupler to Xerox Palo Alto Research Center where Kay helped her edit them on the company's early version of a personal computer called the Alto. MacBird believes this makes her the first screenwriter to edit a screenplay on a computer, but chose the closest approximation to industry standard Courier font available so the studio would think it was typewritten. The character of Alan Bradley was based in part on Kay, and, along with the Stanford Artificial Intelligence Lab, the lab in the film was based on Kay's lab at Xerox PARC. Kay and MacBird married in 1983.
The "User" played by Dan Shor is listed in the credits only as "Popcorn Co-Worker", but information revealed about the possible TRON: Legacy sequel reveals this character's actual name to be Roy Kleinberg.
The trivia items below may give away important plot points.
In the novelization, the final printout Flynn gets is very different from the one shown in the movie; it is more detailed and complicated, shown as a database-like list, and it shows evidence that Dillinger stole several game programs, not just Space Paranoids. The filmmakers may have originally had this list in the film and decided to simplify it so the audience would have no trouble knowing exactly what the printout says. The shots of the printout - and the readout on Dillingers desk computer - are inserts, and a wider shot of Dillinger sinking into his chair looking at the screen clearly shows a readout identical to the one in the novelization. (See also Goofs)
Even though he's not shown, the novelization of Tron states that Sark was present when the MCP derezzes CLU, which explains why he was shocked to see Flynn and calls him an 'ordinary program' even though Flynn is a user. It also explains BIT's reaction to Flynn in the novelization in that the BIT believes Flynn to be CLU.