The experience of going to the movies is only enhanced further when the feature is in 3D—and in Indianapolis, movies include plenty of 3D options. The IMAX Theater at the Indiana State Museum, for instance, shows documentaries and family-friendly movies in three dazzling dimensions and yards upon yards of screen. And AMC theaters around the city include the AMC Showplace 17 IMAX, where movie-goers can experience sizzling summer blockbusters in 3D while also enjoying stadium seating and digital sound.

But before you put on those cool glasses, read on to get a better understanding of how filmmaking technology makes a flat image appear so un-flat.

Isolating Each Eye

The principle behind 3D movies may best be understood via a simple child’s toy: the Fisher-Price View-Master, which brings slides of cartoon characters, natural vistas, and faraway cities to multidimensional life. The binocular-like device isolates each eye so that each receives an image from a slightly different perspective. Before the discrepancy can register consciously, the brain works to unify the two views—creating the illusion of depth in the process.

Filtering the Images

At a 3D movie, filtered glasses perform the task of isolation. The original red-and-cyan glasses, ubiquitous in the mid-20th century, work by filtering out oppositely colored images on the screen. Modern 3D films minimize the color distortion inherent in this process by projecting two versions of the film that alternate more than 100 times per second. Before hitting the screen, each image travels through a polarized filter—that is, a filter that orients light waves in either a clockwise or counterclockwise direction. The lenses of the 3D glasses you don in a theater today in downtown Indianapolis appear identical, but each is differently polarized to let through only one of the two filtered images.

Inventing New Technology

When he first conceived Avatar in 1995, director James Cameron realized that he needed completely new technology to achieve his vision of immersive 3D. Previous filming systems used a cumbersome set up of two full-sized cameras. Rejecting the limitations of movement and perspective imposed by that solution, Cameron invented the Fusion camera system, which uses movable digital lenses that are spaced as close together as human eyes and can move to focus on objects at different depths in the same way.