Movie theater
3D

3D film is a system of presenting film images so that they appear to the viewer to be three-dimensional. Visitors usually borrow or keep special glasses to wear while watching the movie. Depending on the system used, these are typically polarized glasses. Three-dimensional movies use two images channeled, respectively, to the right and left eyes to simulate depth by using 3D glasses with red and blue lenses (anaglyph), polarized (linear and circular), and other techniques. 3D glasses deliver the proper image to the proper eye and make the image appear to "pop-out" at the viewer and even follow the viewer when he/she moves so viewers relatively see the same image.

The earliest 3D movies were presented in the 1920s. There have been several prior "waves" of 3D movie distribution, most notably in the 1950s when they were promoted as a way to offer audiences something that they could not see at home on television. Still the process faded quickly and as yet has never been more than a periodic novelty in movie presentation. The "golden era" of 3D film began in the early 1950s with the release of the first color stereoscopic feature, Bwana Devil. The film starred Robert Stack, Barbara Britton and Nigel Bruce. James Mage was an early pioneer in the 3D craze. Using his 16 mm 3D Bolex system, he premiered his Triorama program in February 1953 with his four shorts: Sunday In Stereo, Indian Summer, American Life, and This is Bolex Stereo. 1953 saw two groundbreaking features in 3D: Columbia's Man in the Dark and Warner Bros. House of Wax, the first 3D feature with stereophonic sound. For many years, most 3D movies were shown in amusement parks and even "4D" techniques have been used when certain effects such as spraying of water, movement of seats, and other effects are used to simulate actions seen on the screen. The first decline in the theatrical 3D craze started in August and September 1953.

In 2009, movie exhibitors became more interested in 3D film. The number of 3D screens in theaters is increasing. The RealD company expects 15,000 screens worldwide in 2010. The availability of 3D movies encourages exhibitors to adopt digital cinema and provides a way for theaters to compete with home theaters. One incentive for theaters to show 3D films is that although ticket sales have declined, revenues from 3D tickets have grown. In the 2010s, 3D films became popular again. The IMAX 3D system and digital 3D systems are used (the latter is used in the animated movies of Disney / Pixar).The RealD 3D system works by using a single digital projector that swaps back and forth between the images for eyes. A filter is placed in front of the projector that changes the polarization of the light coming from the projector. A silver screen is used to reflect this light back at the audience and reduce loss of brightness. There are four other systems available: Volfoni, Master Image, XpanD and Dolby 3D.

When a system is used that requires inexpensive 3D glasses, they can sometimes be kept by the patron. Most theaters have a fixed cost for 3D, while others charge for the glasses, but the latter is uncommon (at least in the United States). For example, in Pathé theaters in the Netherlands the extra fee for watching a 3D film consists of a fixed fee of €1.50, and an optional fee of €1 for the glasses. Holders of the Pathé Unlimited Gold pass (see also below) are supposed to bring along their own glasses; one pair, supplied yearly, more robust than the regular type, is included in the price.
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