The biggest problem with 3D, though, is the "convergence/focus" issue. A couple of the other issues -- darkness and "smallness" -- are at least theoretically solvable. But the deeper problem is that the audience must focus their eyes at the plane of the screen -- say it is 80 feet away. This is constant no matter what.
But their eyes must converge at perhaps 10 feet away, then 60 feet, then 120 feet, and so on, depending on what the illusion is. So 3D films require us to focus at one distance and converge at another. And 600 million years of evolution has never presented this problem before. All living things with eyes have always focussed and converged at the same point.
If we look at the salt shaker on the table, close to us, we focus at six feet and our eyeballs converge (tilt in) at six feet. Imagine the base of a triangle between your eyes and the apex of the triangle resting on the thing you are looking at. But then look out the window and you focus at sixty feet and converge also at sixty feet. That imaginary triangle has now "opened up" so that your lines of sight are almost -- almost -- parallel to each other.
We can do this. 3D films would not work if we couldn't. But it is like tapping your head and rubbing your stomach at the same time, difficult. So the "CPU" of our perceptual brain has to work extra hard, which is why after 20 minutes or so many people get headaches. They are doing something that 600 million years of evolution never prepared them for. This is a deep problem, which no amount of technical tweaking can fix. Nothing will fix it short of producing true "holographic" images.
Murch's arguments are pretty unassailable, and the deficit in 3-D viewing becomes more apparent in home TVs equipped with the capability. Objects in the film are not, after all, actually floating in front of the viewer in three-dimensional space; the illusion merely happens when the viewer's gaze is surrounded by the edge of the frame, creating the appearance of immersion. When the edges of the frame are more easily seen and moved past -- as is the case with TVs -- the illusion is that much easier to break.
Yet I think Murch is missing the larger point here; in other words, I agree with him, just for slightly different reasons. It's true that 3-D exhibition makes for darker, murkier images than you'd normally get from a traditionally projected 2-D film, and when coupled with the dearth of skilled projectionists and a growing tendency for theaters to project films dimmer than they were intended to be seen in the first place, it's not uncommon for the 3-D viewing experience to be a bleak, blurry affair. When attending recent 3-D films for review purposes, I've occasionally raised my glasses for an instant and been shocked at how much brighter the unfocused image is. Watching a movie through a pair of dark lenses is as crippling as you'd imagine.
However, Murch's complaints focus almost entirely on the technical aspects of exhibition. This isn't surprising; he's a technician, and is approaching the question of a new piece of technology from the perspectives of quality of implementation. As a critic, though, I find myself more drawn to examining 3-D from a narrative or structural perspective. In other words, how does 3-D serve the film itself?
The short answer: poorly. Backing up a little: There's a debate within the debate over 3-D that discusses the merits of films composed and designed to be exhibited in 3-D versus those that are converted in post-production to the format, with defenders of the middle-ground saying that 3-D might not be as wonderful as the studios would have us believe, but in certain instances it can be worth it. Slate's Daniel Engber mentions in his recent column on 3-D movies that there's a moment in Toy Story 3 -- which was shown in 3-D in many locations since it was conceived to play both ways -- in which the emotional distance between Lotso and his former owner is heightened by the third dimension added between their bodies. More than that: he argues that the scene only works this way, writing that if "the screen were flat, Lotso and Daisy would be right next to each other on the screen." Engber is trying to argue that a two-dimensional image is somehow unable to convey geography, as if seeing two characters separated by a pane of glass is impossible to decrypt without the added benefit of digital trickery forcing the viewer's brain to separate them in the air. This is a myopic assessment that ignores the fact that the characters were standing in different areas within the fictional world and takes for granted the fact that no one would actually have been confused by the two-dimensional scene. He's conflating a flat image with a depthless one, forgetting that focus, depth of field, and basic human comprehension are a whole lot stronger than he remembers them to be. The characters appear to be "right next to each other" only in the most basic sense that they are in different parts of the frame. Come on, Engber. Give us all some credit.
Why is that poor service to the story? Because it's redundant. The real idiocy of 3-D isn't (just) its dimness, or shoddy production, or the way it can induce headaches in even the most dedicated viewers. It's that it adds nothing to the story. Not a thing. There isn't a line of dialogue that gets better when the speaker is digitally made to appear floating above your head; there isn't a moment between a man and a woman that becomes more tender when the room behind them is forcibly made distant; there isn't a prodigal homecoming made better because father and son seem to fly. Proponents of 3-D are mistaking presentation for content; special effects for story itself.
A film presented in 3-D isn't more real, and in fact, the digital rigging requires such additional work from our eyes and brains that it's never far from our thoughts. Watching a 3-D movies, we're constantly thinking on some level, "I am watching a 3-D movie." Yet fans of 3-D never stop to think about the fact that film is already able to use the moving image to create believable, realistic, deep spaces on its own. The rapid projection of images, each slightly different than the one before, already creates a realistic world for our brains. We know we're watching a filmed entertainment, but we also recognize that the people, buildings, etc., actually exist in real space. In a 1998 piece in The New Yorker, critic David Denby wrote that "photographic images that move in real time still carry a freight of actuality that others do not.... Sorely literal, we cannot shake the naïve habit of reacting to images as if they actually referred to something; we still quail when a woman gets punched in the mouth." Pissy, but accurate. Film mimics our world and takes us to new ones, and it does so with such ease and grace that we're able to be drawn into the story and to let go of the conscious work that 3-D requires. The medium is special enough on its own.
Ultimately, 3-D is nothing more than a special effect, hastily applied. Ironically enough, the most pointed summation of the problem and the best approach to special effects in general came from George Lucas, decades before he'd ceased being a writer-director and become a lost and somewhat befuddled king surrounded by yes-men. He said, "Special effects are just a tool, a means of telling a story. People have a tendency to confuse them as an end in themselves. A special effect without a story is a pretty boring thing." 3-D is an effect. Period. A good film doesn't become better by virtue of being presented in 3-D. The first Pixar film shown in 3-D was 2009's Up, and 3-D had nothing at all to do with its moving story, heartbreaking moments, or uplifting finish. Gimmicks don't elicit deep emotional responses. We bring ourselves to films and leave changed by the characters we meet on screen, not the tricks that exhibitors force upon us. The stories that move us and that stay with us do so because of what they're about and the way they're about it, not because the images were blasted at us in blurry, fake, distracting attempts to trick us into thinking we're having a real emotional experience. Film is an emotional medium., and 3-D is an attempt to replace emotion with assault. It's all flash, and no substance.
Daniel Carlson is the managing editor of Pajiba and a member of the Houston Film Critics Society and the Online Film Critics Society. He's also a TV blogger for the Houston Press. You can visit his blog, Slowly Going Bald.