A classic analog film shortcut led to iconic outer-space blaster effects
The original Star Wars films employed many iconic and memorable visual effects that make those movies feel like Star Wars to us. Famously, they were all “practical” special effects — no computers involved — including a lot of complex optical printing and in-camera cleverness. Here’s a brief explanation of one of the simplest of those effects, a tiny bit of filmic sleight-of-hand, the origin of which you must examine the actual film stock to understand.
Here’s a very short clip illustrating the way that blaster explosions resonate on screen with a white-light pop to indicate that the beam hit something:
In many films, explosions are coded as “fire” using reds and oranges, so there’s a specific stylistic element to these flashes.
What are you really seeing when the blast strobe occurs? You might think it’s some sort of carefully hand-drawn matted animation, some sort of blooming imagery pulled from the mind of George Lucas? Nope. The best film tricks are often the simple ones. Need a hint? That strobe flash lasts for exactly 1/24th of a second.
Here’s a magnified look at a print of Star Wars that was struck from original negatives — it’s a detail from the sequence embedded above:
It’s just a single blank frame! The light burst you see (or would have seen, if you’d been sitting in a theater in 1977) is simply the projector’s bulb light shining evenly through the film acetate for the duration of a single frame. Theatrical film runs at 24 frames per second, which means the blaster strobe is necessarily pegged to that fractional time value. So much for outer space physics.
(OK, if you look closely, technically you can see that it’s not the clear acetate but a white-colored frame. You don’t want the lack of control that clear acetate would create.)
Here are a couple more instances, occuring in brief succession:
