Today is “Back to the Future Day;” October 21st, 2015. This is the day that Doc and Marty traveled to the future in Back to the Future 2. That film was a visual effects extravaganza, featuring incredible optical composites of future skylines and flying cars, matte paintings of ruined cities, detailed miniature and model setups, and incredibly complicated motion control shots that enabled actors to interact with themselves in old age makeup – all before the days of digital animation!
The original Back to the Future, on the other hand, despite being a classic sci-fi time-travel film, only has about a dozen visual effects shots. Its effects are basically limited to the lightning in the sky above the clock tower, the lightning bolts traveling along cables, and the sparks and comets that surround the DeLorean as it accelerates to 88 miles per hour to break the time barrier. All of those effects were managed by Industrial Light and Magic animator and supervisor Wes Takahashi, and then composited together by John Ellis’s team on ILM’s massive optical printers.
Takahashi created these effects rather simply, by drawing black lightning bolts frame by frame on the white paper with ink pens and airbrushes. When his animation was photographed, the negative of the film could then be double exposed on top of the footage of the action from the set. With a few layers of diffusion and some smart color timing, the effects are very convincing. While the meticulous process of building these effects was very time-consuming in the pre-digital age, they are elegantly simple.
And the crafting of that film is also elegantly simple, director Robert Zemeckis using these very few effects very effectively in the service of the story. You can read an interview with Wes Takahashi over on FX Guide, and learn more about his process and see clips of his work in the final movie.