A pioneering early "slow-mo" technique was developed only as padding

Lost for decades, the sword-and-sorcery short film that showed before Star Wars: The Empire Strikes Back is finally being shown again at the Mill Valley Film Festival. And it turns out the most innovative thing about Black Angel, a technique for slowing down the fight scenes, was purely to pad out the length.

Black Angel, directed by Star Wars/Alien art director Roger Christian (who later directed Battlefield Earth) was famous for pioneering the use of "step-printing" to slow down the action in the fight scenes. George Lucas was so impressed with this technique, he used it in Empire Strikes Back, as well.

But as Christian explains to Ars Technica, the reason for slowing down the fight scenes wasn't to make them look cool — it was to make the short film long enough:

There wasn’t enough initial material for Black Angel to fill the required 25-minute runtime. “So we slowed down fight scenes in it to build up the time,” Christian said. They did this through a technique called step-printing. Strategic scenes are shot at a slower film speed so action is sped up, then frames are printed at a slower speed onto the finished film. Action becomes very fluid, with individual moments seemingly smearing together with the next.

“I’m just happy Alan showed me how to step print in those days. I loved the look; it just transformed into some mythic areas,” he said. “But literally that was because we didn’t have enough film to up the time to the 25 minutes it had to be. All this was running through my head during the first screening, but Lucas absolutely loved it. So did other people.”