Imagine it’s 1966... this director named Stanley Kubrick comes up to you and says, “I want you to create the Stargate sequence for my new film, 2001: A Space Odysseey where Dr. David Bowman travels through time and space before landing in a cosmic zoo and ultimately being reborn as a Star Child.
Yeah Buck Rogers this ain’t. No film at that point treated space travel so seriously.
Oh Well this shouldn’t be too hard... We’ll just pop open After Effects, drop in a couple pieces of artwork, throw on the 3D camera and animate it flying through this stargate tunnel.
Oh wait, it’s the mid sixties and the computers at the time were the size of living rooms and had less computational power than a modern calculator. Kubrick was making a serious space film and he didn’t even have a full picture of Earth as seen from space - this famous one, the blue marble - the first of it’s kind, was snapped by Apollo 17 Astronauts in 1972
How was this stargate effect created by the real life 2001 visual effects supervisor Douglas Trumbull? Well to find the roots of this technique we need to go back to mid 1800s and the origins of slit scan.
Slitscan in Photography
The Pioneers of photography in the 1800s were apt to try all sorts of experimental techniques including a technique called slit scan. Slit scan is the process of putting a sliding slit between the subject and the photographic plane. The photographic medium under the slit would be exposed as the slit travelled from one side of the frame to the other.
One of the earliest uses was for panorama photography. Originally developed Joseph Puchberger in Austria of 1843. the Ellipsen Daguerreotype, was a swinging lens system to capture 150 degree views onto 19-24 inch long plates - keep in mind this is the era before flexible cellulose film. The following year in 1844, Friedrich von Martens, a German living in Paris, made the Megaskope camera a similar device using a swinging lens but controlled by gears and handles.
But slitscan really started to gain popularity when flexible film came into use - especially as a relatively inexpensive way of creating panoramic shots. By the turn of the century, cameras were developed with that ran the film along a curved imaging plane. The Slit would then orbit around this curved image plane creating a panorama.
Slitscan had other uses as well - one really really important use was at the Race track. Gambling on races had become very popular in the 1940s and avoid the air of corruption in tight finishes, race tracks needed a photograph of who came in first. Contrary to what movies or cartoons depict, these photo finishes weren’t just some guy with a flash bulb at the finish line and a hair trigger. Instead they used a variation of the slitscan called Strip photography.
Strip photography uses a stationary slit and the film is moved underneath.. This photo created a record not of spatial relationships but of temporal relationships - time. The slit doesn’t move - only what’s in front of it. So when you look across the photo, you are looking at the exact same spot only recorded at over a period of time - the slit scan concept and it’s digital derivatives continues to see use today in race tracks around the world.