It’s a little silly to be writing a third post about Avatar, particularly after seeing Up in the Air over the holiday and regaining some perspective on what movies can actually do. But this is about technology!
After Avatar we sat around Rocket Bar, snapping the 3D glasses in half and trying to recreate the day we spent screwing around with polarizing filters in middle school physics class (though more drunkenly this time). As with all 3D-via-2D-surface technology, different images need to be delivered to each eye, and since the glasses weren’t the stupid red/blue combo from days of yore, we figured that they were doing so by delivering left-eye and right-eye frames in different polarities of light, with correspondingly different polarizing filters to keep the signals distinct. Combining the two filters ought to have let us filter out all light. Or so the classic experiment goes.
But it didn’t work! Well, maybe it did, a little. When you put the lenses in front of each other and rotated one 90 degrees, there was a noticeable dimming, but not the total blackout that I expected.
Today a gentleman named Daniel posted some information to the HacDC list explaining what’s going on: the light isn’t linearly polarized, it’s circularly polarized. I can’t claim to really understand this, but the relevant wikipedia page contains a diagram that almost fools me into thinking I do. More from Daniel:
… circular polarization is a lot like linear polarization and unless you’re viewing circularly polarized light it IS a linear polarizing filter. However if you’re viewing circularly polarized light then the benefit over linear-only is that you can turn your head from side to side without losing the effect (not real clear on how this works). RealD’s breakthrough was in coming up with a cheap way to combine the linear filter with a quarter wave plate in one package without costly lamination, so they’ve brought the more advanced circular technology into the mainstream by making it affordable. However, there is additional cost in that the screen has to be coated in aluminum paint or something that will reflect the light while maintaining polarization.
Interesting! The RealD wikipedia page fills in some more blanks. There are really only four parts to the system: a high-end digital projector that can manage crazily high frame rates and which your theater has hopefully already bought; the aforementioned polarity-preserving coating on the screen; a polarizing filter that sits in front of the projector, rapidly flipping between directions of circular polarization as right eye/left eye frames pop out of the projector; and the glasses, which are just specially-treated plastic. So there you have it.
What may be even more interesting than RealD’s tech is how this will all play out in the home theater space. Matt told me that he’d spoken with his dad, who’s a screenwriter (among other things), and that the industry is extremely excited about the prospects of Avatar because people can only get the 3D experience in the theater — and anything that can prop up the perpetually-ailing (but completely essential-to-the-industry! for reasons of history, vanity and stupidity) theater business will be very welcome indeed. So it’ll be nice to have that precious 3D magic bottled up in the theaters, ensuring a steady stream of fat-walleted rubes.
Except, of course, that the Avatar videogame, which you will play at home, is going to be 3D. Actually, this is technology that’s been out for a while. Rather than fancy alternating-frame polarization, which a normal TV can’t manage, the viewer wears glasses with LCD shutters that snap on and off to control which frames each of her eyes sees.
This kind of setup doesn’t appear to be particularly cheap at the moment — you need some wireless syncing stuff in there too, not just amped-up solar calculator technology — but it’s certainly not unattainably expensive, and you can bet that the price will drop tremendously when someone begins pushing this as an essential home theater amenity and not just a niche gamer accessory. For all I know the Avatar game will drop the price considerably — I imagine it’ll be shipping SKUs that include the glasses.
And at that point, it’s hard to imagine that the industry won’t shoot itself in the foot, reenabling piracy when it foolishly decides to buy whatever DRM snake oil it’s being pushed by tech company salespeople to excuse the lucrative sale of Blu-Ray 3D discs. I mean, sure, in-theater cam work would be more difficult with a 3D film, but this stuff is getting distributed digitally anyway. I suspect we’ll see 3D torrents within 8 months of the first home theater-compatible 3D movie release. Then we’ll see some codec adjustments to make the formats more space-efficient, and then we’ll be back at the status quo. And then, as the joke must inevitably go: on to Smell-O-Vision/the iTablet/whatever, the new savior of the film industry. I just hope this silly 3D cycle completes its run before I’m forced to buy any stupidly 3D-capable audiovisual equipment.