The cinema, television, and streaming have extraordinary tools at their disposal that would have been considered pure magic 40 years ago. Back then, technical limitations were solved with sheer creativity and experimentation, producing results so good that even today they are identified as primordial CGI. In an old article for Cartoon Brew, Neil Emmett shared some examples of Pseudo-CGI, starting with an iconic and unforgettable character from the '80s...
Obviously, it's Max Headroom. First there was the movie, then the show, and finally the series, but beyond changes in format and the passage of time, Max Headroom always remained constant. Those who don't know its background and see it for the first time might conclude that Max is the product of very basic CGI, however, there is no animation here...
Pseudo-CGI: Creating Fake Computer Animations
What appears on screen is the actor Matt Frewer himself, with lots of latex, and a shiny suit made of fiberglass. His voice was processed with a harmonizer, and half of the frames were removed in production, creating a more believable animated effect. The only digital thing was the background.
Another example cited in the article is Escape From New York, the 1981 classic. When Snake Plissken begins his flight to sneak into the city, the screens show a kind of digital reproduction of Manhattan, but that digitization is also fake: In reality, they created a scale model, covered the edges of the buildings with reflective tape, and filmed the scene under ultraviolet light.
Still, the most popular case, and I'd dare say the most mediatic, was Tron. The original 1982 film took the potential of backlighting to the limit, and combined with live-action performances, the final result seems to have been digitally processed. Of course, Tron includes real CGI, but it's estimated to represent about 15-20 minutes of the film. In fact, technical limitations were so great that creating a single frame could take up to six hours.
Source: Cartoon Brew