Behind the 3D Scenes

What does it take for viewers to see more than the usual two dimensions on the big screen? The answer is simple: two pictures shown at once and a pair of glasses to see them with. But it's a bit more complicated than that.

When a 3D film is produced, it is filmed either with two cameras that are calibrated to capture the same picture but with a small lateral difference, or with one camera with only one lens but that can capture two pictures at once. Meaning that the effect is created during the filming and not done afterwards.

When the film is then shown at the cinema, different 3D technologies can be used, but the polarizing technology that SF Bio uses is one of the newest. It requires a 3D system that is installed in front of the projector and with the help of a filter "divides" the pictures so that there are two projected onto the screen in parallel. When moviegoers have a pair of 3D glasses on that can polarize the light reflected off the screen, the two pictures hit the eye at the same time. That's a total of 72 pictures per eye per second - 144 pictures total.

Even if there is 3D technology for analog film viewing (with a 600-meter-long and 35-millimeter-wide roll of film that is clipped together to pass through the projector), SF Bio is investing in digitalization of movie theaters, because the quality is so much better. The establishment of 3D movie theaters and digitalization go hand in hand. Showing 144 pictures per second doesn't work with a traditional film roll, because the switching from frame to frame is mechanical - mechanical projectors show a total of 48 pictures per second which means a 35mm film looks as if it is in low resolution if shown in 3D.

SF Bio has invested in digital technology at all its theaters where there are 3D screens. A total of 46 cinemas around Sweden are digitalized, and at 38 of these there is at least one screen showing 3D films. At the end of May there will be at least one 3D cinema in each of the 22 areas that SF Bio has theaters. But there is a lot of work involved in digitizing what goes on in the projector room of movie theaters.

"The first thing we usually need to change is the amount of space," says Kullander. "It's built for a 35mm projector - just one machine - but now a lot more stuff needs to fit, so we need to enlarge the space. Aside from the projector, there is a server for the film and a media player that sends the pictures to the projector. Today's servers have about 1.3 terabytes, which can handle five to six films.

"There are so many films coming out in 3D now that we aren't able to show every film as long as we could. The next Harry Potter film will be in 3D and come out in November, but already after about a month the film will need to make way for other big films that are premiering before Christmas."

Kullander also believe that 3D glasses will be further developed and be easier to use. He explains that a number of different sunglasses manufacturers are working with creating glasses that can be used both to protect from the sun and for a visit to the movies, and would of course be used many times. Today SF Bio gives moviegoers one-time-use 3D glasses that are collected afterwards and recycled.

"It's already a big difference between the current glasses and the old green and red lenses you used when 3D came in the '80s," says Kullander. "Many who are coming to see 3D films now think that it's still the same thing, but the experience is totally from what it was. And our glasses are chosen with the customer experience in mind: We want it to be comfortable to look at a 3D movie."