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3D at the movies
Mike Trickett
he perception of depth, the ability to
Tperceive the world in three dimensions,
comes naturally to humans because each of our
eyes, set about 70 mm apart, sees a slightly
different view which, when combined by our
brain, gives us the perception of depth. The
closing of one eye removes that perception.
The means by which three dimensional (3D)
images (sometimes called stereoscopic
imaging) can be recorded and viewed has been Various devices offering this were popular in
known for as long as the recording of the late 1800s through to the mid twentieth
photographic images has been possible. century. All of these items were for direct
viewing of the images by a single person and
relied upon the device’s ability to convey the
left and right image to the appropriate eye.
The viewing of a 3D image by a large number
of people is a far different matter. The
projection of the two images required to form
a three dimensional image is a simple enough
matter, but to ensure the viewer sees only the
left and right images with the correct eye
requires a method of separation, achieved by
the wearing of some type of glasses
Hand held stereo viewers were a very popular incorporating suitable filters. A number of
item from the 1880s to the 1920s.
systems were devised, tried and faded away in
The recording and direct viewing of a 3D the years prior to what could be called the 3D
image is a fairly straight forward procedure. A frenzy of the early 1950s.
camera or cameras with the lenses separated by
roughly the same distance as our eyes will The 1950s brought a number of changes to the
record two slightly film industry (larger screens, stereo sound,
different images etc), many of which were an attempt to counter
which, when viewed the impact that the introduction of television
separately by the left (in the USA at that time) had on cinema
and right eye, will audiences. Three dimensional films were just
recreate that 3D one aspect of that innovation by the industry.
image.
The recording of motion in 3D requires the two
images to be recorded on film or films in
perfect time with each other. In the case of a
The stereo viewer
was a popular family color film, the two images must be matched for
entertainment item in the same color rendering. Cinema projection
the late 19 Century could be a problem, as perfect alignment of the
th
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