Anaglyphic System
In a red/blue 3-D film, the movie is
created to display two images superimposed
on one another
, one is projected in red, and the other is projected in blue
(or green).
3-D glasses are worn so that one image will enter one eye, and the other
image will enter the other eye. The brain will than combine the images
together, and a 3-D image is seen. However, because red and blue color
projections are used to separate the image, the movie is not in color (4).
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Polarization System
Modern day 3-D movies project two different images on the screen that have polarization directions which are perpendicular (90 degrees) to each other. 3-D polarized glasses are worn that have a different polarization in each lens which allows only one image into each eye (4). One side will only allow horizontal light to pass through, and the other side will only allow vertical light to pass through. Some 3-D movies are filmed with a special 3-D camera that uses two films and two lenses and only captures two directions of light. This captures the scene twice, with two different polarization's. Other movies are filmed with two cameras at slightly different locations. The film must be projected on special material so it does not loose its' polarization. A Silver stripe screen is the most common.
Another system of producing 3-D movies
has been developed more recently, called the LCD (Liquid Crystal
Display) Shutter system. It is most often used in video and
computer game technology and not for movies because the equipment is
expensive. The LCD shutter glasses are connected by cables or
wireless to a monitor that syncs the glasses with the image being
projected. When the monitor is displaying an image for the
right eye, the left eye shuts off, and when an image for the left
eye is displayed, the right eye shuts off. All of this is
switching back and forth at about 60 times a second, so the result
is a flicker free 3-D image. Other types of shutter glasses
that don't involve LCD are also available, and they use the same
principle to create a 3-D image (2).
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