The official Matrix website will gives you the straight dope about the Bullet Time Walk Through special effect.
If you’re referring to the Gap ads, that is not bullettime. Time stops during that effect while time continues to run during bullettime.
How did they ‘remove’ Gary Sinese’s legs in Forest Gump?
Gary Sinise wore blue “socks” on his lower legs and they used the blue-screen technique mentioned previously to paint the proper image in place of his legs.
Neat, thanks! Your power over the internet is most impressive.
Long loooong before the Gap Ads. Which I’ve never seen, of course, because we don’t have ‘Gap’ down here.
So they varied an already long established effect into their own version. They slightly altered it to suit their film. i.e. they perfected it. It can’t be claimed they ‘originated’ it.
Naturally this was the first thing I considered, but there are scenes that look like the blue screen technique would be impossible - like being unable to see his legs against his wheelchair (for the bluescreen non-sinise shot they’d have to make the wheelchair move exactly the same as it does with sinise in it). And other reasons I can’t remember off the top of my head.
When he’s in the wheelchair, he just has his legs folded under him, like he’s kneeling on the seat.
For the scene where he climbs into his wheelchair, I’m not sure, but I think they locked the wheelchair into place. What they normally do is film a ‘clean plate’, which is a shot, with camera movements, without the actors in it. Then they shoot it normally with the blue-socked actor.
The blue sock usually isn’t for keying, so much, as easily distinguishable from the other parts of the shot. They’ll then go in and frame-by-frame replace (paint over) the missing leg using details from the clean plate.
There are variations of that method for getting it just right (sometimes they’ll computer generate props and totally replace elements with them to give them more control and consistency) but that’s basically how most digital effects like this are done these days.
Forrest Gump’s Special Effects
The DVD of Forrest Gump has a section about the special effects, too.
Poppycock. Film can last over 100 years and stay in terrific shape (I’ve seen it firsthand). It’s only unstable when you don’t take care of it. It’s much more reliable than magnetic tape and more proven than any digital media out there.
You can do your own cheapass “bullet time” shot in a small familiar room with much patience. You’ll need a long strip of unexposed film and a strobe light with a triggering device on a long cable.
Prepare the room with some small hooks in the walls, tracing a long spiral line around all four walls. Then turn out the light and practice finding the hooks in the dark. When you are sufficiently confident, hang the film on the hooks (keeping in the dark, naturally) so it wraps around the room several times.
Then take the strobe light trigger in your hand, jump, and press the button while you are in midair. All the film is exposed at once, so after you collect and develop it, you should have a shot of yourself as if hovering in midair while the camera rapidly circled you. If your film strip is long enough, the circling could easily got for ten or more revolutions, causing massive nausea in your audience.
It should make an interesting afternoon project for the film geek with nothing else to do.
But see, ArchiveGuy, that’s the point: most people don’t take care of film. I can’t count the number of movies and TV shows from the last 25 years I’ve seen where the colors are already badly faded, for example.
Plus black & white film is considered to be archival, much more so than color. And all that 100 year old film is surely b & w…
Be that as it may, calling it “pretty unstable” is inaccurate. If I leave a car unattended in the heat and rain for a decade, you can’t blame the auto manufacturer for whatever toll that neglect takes.
And it has been common practice for many years (especially with the surge of video) to make quick, down ‘n’ dirty transfers from poor quality prints–prints that were often on long theatrical runs before winding up as a transfer source. This is not a testimony to film’s instability–it is a testimony to the studios who value saving a buck over going to the trouble of finding a quality, pristine print.
I am a professional film archivist, so you don’t have to remind me of the dearth of care many films receive. However, in your original post, you simply stated that “film is a pretty unstable storage medium”, as if the poor quality and gradual deterioration is a natural inevitability. This is far from the truth.
As for SmackFu’s comments, it depends on what kind of color you’re talking about. Tints, tones, and 2- and 3-strip Technicolor are much more stable than the more recently developed Eastman color, so yes, fading would be more of a concern for films from the last 25 years. But that still doesn’t change my answer above: stating that it’s “unstable” as a foregone conclusion is a gross oversimplification.
ArchiveGuy, we’re both right; we’re just talking about different things. You’re talking about preserving things in archival conditions, while I’m talking about typical conditions. You’d be absolutely right if all films were stored in archival conditions–but of course, virtually all films are/were not stored that way (sadly) and thus age relatively quickly.
I must also admit that the implicit comparison I had in mind was to text, where the information can outlive the artifact indefinitely. A particular copy of a book may be doomed to crumble into dust, but the text of that book can be copied and then stored with good fidelity for long after the book itself is gone. Copying film is (at the moment) relatively more lossy.
Well, sure, if you’re comparing them to books! I can’t compete with stone tablets either! (though film is a bit lighter to carry) 
Again, if you’d like to see the technique (as described by censored and Walloon) demonstrated, get a hold of the Pleasantville DVD.
In the absence of a lens, what focuses the light on the film?
Bryan Ekers, did you actually try that homemade bullet time yourself? Because it wouldn’t work. All of the film would be uniformly exposed. You can’t make a movie that way any more than you can take a picture just by holding up a piece of film to the image. You need a camera.
And what about mixed black-and-white and color in old (pre-computer) movies? The Wizard of Oz comes to mind, here.