[Philip Lelyveld comment: this 4 min video discusses and shows polarization, IMAX v 35mm film, silver screen, and projector/lamphouse technology]

[Excerpt from accompanying text] This segment shows how IMAX 3D experience is created. Note that most IMAX theaters popping up in recent years use IMAX digital projector. No film is involved, hence portions of this video do not apply to those new theaters. Digital IMAX movies are transported by multi-giga byte computer hard disks. Many new IMAX screens are about 40 feet tall which are only half the height of the 80 feet tall screen depicted in this video. Traditional IMAX theatre is usually a 8 story tall building you can spot from blocks away.

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