The Dark Flaw in 3D’s Bright Future

A typical 3D movie can be 80 percent muddier than its 2D counterpart — it’s driving away theatergoers, and a solution could be costly

3D may be the bright shining future of the movie business, but at the moment it just isn’t bright enough.

That’s not a metaphor. It’s the plain truth.

3D movies — whether they’re made using the process or converted in post-production — are simply screened at significantly lower light levels than 2D films. 

Inception poster

More and more often, it’s enough to hamper audience enjoyment, make filmmakers wary, and perhaps even slow down the acceptance of a format that is one of the movie industry’s great hopes for the future.

When Roger Ebert blasted 3D in an article in Newsweek, for instance, one of the reasons he listed for disliking the format was “its image is noticeably darker than standard 2D.” 

Even a movie like “Avatar,” which was shot in 3D using techniques that boosted the amount of light and compensated for the darkening process to come, was screened at light levels about half of a run-of-the-mill 2D film.

And the problems are exacerbated when a movie — like the disastrous “Clash of the Titans” — is made with no thought of 3D and hastily converted after-the-fact. "Titans"appeared so muddy that it prompted walkouts and no doubt scared some theatergoers away from the 3D experience entirely.  

(Fewer and fewer moviegoers are making the 3D choice when they plunk down their money at the box office; see sidebar: "The Rise and Fall of 3D.")

At the Hero Complex Film Festival in downtown Los Angeles in June, “Inception” director Christopher Nolan joined the 3D naysayers, saying that he refused to make his new film in the format largely because of the darkness problem.

“On a technical level, it’s fascinating,” Nolan said of 3D, “but on an experiential level, I find the dimness of the image extremely alienating.”

The 3D process, Nolan said, makes “a massive difference” in the brightness of the image. “You’re not aware of it because once you’re in that world, your eye compensates – but having struggled for years to get theaters get up to the proper brightness, we're not sticking polarized filters in everything."

Nolan also got into the numbers, using “foot-lamberts” – the unit of luminance by which screen brightness is measured – to explain the difference between regular and 3D projection. But when he said that traditional 2D cinema is projected at 16 foot-lamberts, but 3D automatically loses three foot-lamberts, he was grievously underestimating the 3D effect.

In fact, a typical 3D system can lose as much as 80 percent or more of the light from a 2D system on the same screen, and result in an image projected at only two or three foot-lamberts.  

“I think it’s a major problem for the audience appreciation of 3D,” says Lenny Lipton, a pioneer in the field since the early 1980s. “The principal complaint that audience members and industry people make is that it’s too dark.”  

Here is a primer on what happens with 3D projection:

The figure of 16 foot-lamberts is the standard established by the Society of Motion Picture and Television Engineers for a projector with no film in it. If you add a 2D film to a projector that meets the brightness standard, you’ll generally wind up with about 14 foot-lamberts, considered an appropriate level of illumination.

3D projection, though, displays two separate pictures, one designed for the left eye, one for the right.  Some systems – for instance, projectors made by Texas Instruments – display the two pictures sequentially, in rapid succession; other systems, such as Sony’s, display the pictures simultaneously. Both systems then use glasses to merge the two images into one three-dimensional image. 

But whichever system is used, the immediate result of dividing the picture into two images is that, in Lipton’s words, “You lose half your light, because half the light goes to one eye and half goes to the other.” Instantly, a 14-foot-lambert image is reduced to seven. 

3D screeningThe glasses used to decode the two images, whether they use RealD’s polarization method, Dolby’s spectral division system or any of the other systems on the market, then cut the light further.

“Avatar,” says Lipton, generally screened at about four-and-a-half foot-lamberts; other films are as low as two or three.

And if the film was not originally shot in 3D, at which time the director of photography could add light and change the gain to compensate, the darkness is emphasized even further – hence the infamous “Clash of the Titans.”

“It’s a huge light tax on every system that’s out there,” says Doug Darrow, the CEO of the New Hampshire-based company Laser Light Engines. “And the reality is that while 3D has been a huge success with the audience, the current technology just can’t keep up with it. You can’t get a bright enough image, therefore the 3D effect isn’t as good as it could be, so they’re not getting the full immersion that they should.”

While it’s unrealistic to expect 3D presentations in the full 14 foot-lamberts, most in the industry agree that 2D should be shown at about 14, and 3D at 10 or above. But with big screens, that virtually never happens for 3D exhibition, which at best is shown at about one-third the light level of a 2D presentation.

“Fourteen foot-lamberts is a decent picture,” says Lipton.  “Half of that, you’re doing fine.  But a third of that, you’re kind of getting hairy.  And when you get down below three foot-lamberts, you start losing your color vision, and the images are appalling.”

Adds a studio executive who works with 3D but asked not to be identified, “It is not the optimal presentation, and lots of people share that concern.” 

So what can be done about it?  The problem, says the executive, is that you can’t just put in bigger light bulbs or turn up the amperage to the light source; that would cause problems with heat, among other factors.

High-gain screens, which are used by RealD among others, can boost the brightness by a couple of foot-lamberts – but that only takes it into the barely-tolerable range.  “If everything’s running optimally and the projector is running to spec, those systems can do about five foot-lamberts,” says Lipton, who helped develop the RealD system in his days with that company.

Some theaters link two projectors; IMAX does it this way, but the solution requires more space, more power, a more accomplished projectionist and significantly more money — and it still ends up with luminance below the recommended standard.

Lipton is now working on the Oculus3D system, which he says will be “two or three times brighter” than most systems. “It can all be solved,” he insists. “The technology is there.”

Imax 3D posterAnd last week, IMAX announced its investment in Laser Light Engines, a system originally developed for military use. LLE’s Doug Darrow  says his company’s system currently exists in prototype form on a relatively small screens – but when developed for large screens like IMAX, says Darrow, the use of laser light “can make digital projectors three to five times brighter than they are today, which means we’ll have no problem lighting up 3D screens with the spec brightness.”

(Laser light has its own technical problems, chief among them a interference pattern called “laser speckle,” which Darrow says his company has overcome.)  

The laser solution, which is being investigated by other companies besides LLE, has the support of at least one of the studios making the heaviest push for high-quality 3D.  "The most promising work in the field," says Chris Cookson, the president of technology at Sony, "is being done by companies who are creating laser light sources for theatrical projection."

Of course, if the solution to the 3D darkness problem lies in lasers or some new technology, that could be a costly solution for the thousands of theaters that have spent the last few years upgrading to expensive, lamp-driven digital 3D systems. 

“We have all these 3D movies coming out, but it’s entirely possible that the digital conversions and computer technology that exhibitors pumped a ton of money into are now obsolete,” says the producer of a film that has done well on 3D. “That would be a catastrophic economic situation, but I bet it’s what you’re going to find.

“Three years ago the push was to digitally upgrade every theater – but at least for the moment, theaters don’t have the necessary horsepower to show the movies in the way that people are now thirsting for.  So you’ve got laser companies stepping in, or people patching together two projectors to replace things that were just done in the last three-to-five years. It’s crazy.”