CHAPTER 13APPLIED STEREOSCOPYS’
and
’EREOSCOPIC reproduction is not at all limited to the amateur
photographer. It finds a wide application in the diagnosis
treatment of diseases and maladjustments of the visual appa-
ratus. It is used to excellent advantage in military work, particu-
larly in aerial photography. In advertising it has already gained
high favor. Students in schools obtain visual impressions of places
and objects which could not be obtained in any other way.
Scientists have found it to be the only photographic method
which meets their demands fully. In the medical profession it
is widely used for teaching purposes,-and hardly an X-ray installa-
tion is without its Wheatstone viewer for stereo X-rays. Stereo-
scopic photography is now being used to record installations in
factories, keep check upon field work by engineers, record results
of scientific work in the field, and of course in the more elaborate
stereogrammetry it is used for actual surveys.
New applications are appearing almost daily, not the least in-
teresting being its use in recording evidence for both civil and
criminal trials.
THREE-DIMENSIONAL VocuE.-It is now the fashion to use the
term “three-dimensional” in both apt and inapt connections. No
phrase used in the discussion of pictures has been more over-
worked or more abused. Very serious efforts have been made to
convince the public that three-dimensional pictures are something
quite new, and totally different from the old stereogram. They
either ignore or do not know the fact that any truly three-dimen-
sional picture must be stereoscopic, for the latter term is spe-
cifically descriptive of “depth vision.” It might be remarked in
passing that the phrase “three-dimensional” is often applied to
systems which are unsound, and even to some whose only pretense
to relief consists in the name itself!
It must be added, however, that there are three-dimensional
pictures which are certainly not ortho stereoscopic.
Although “three-dimensional” is less specific than stereo, it is
better known and is recognized by those to whom the word
“stereo” means nothing. At the same time the almost universal
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