STEREO MOVIES 287ous to learn how it will be received by the public. It is his firm
conviction that once the public has seen stereo they will not be
satisfied with the prancing shadows of the flat screen and will de-
mand stereo just as today they demand sound. Time alone will tell
if this will happen-but I think and sincerely hope, it will.
SUMMARY.--I. The film is made normally, using a stereo re-
flector of the type used for still photography with a single-lens
camera. The individual images are a half frame in width and
hence the screen image will be abnormally high and narrow un-
less use is made of a system just devised whereby optical or mask-
ing means are utilized for overcoming this narrow format. The
film is projected either through a prismatic lens or through the
stereo reflector, each image being polarized at right angles to
the other. Polaroid spectacles are used for viewing the images,
which are projected upon an aluminum screen.
Fig. 19-8. The projector-reflec-? P
tor. The Polaroid filters, P-P,
have been added to Ihe stand-
ard reflectors and the’ outer mir-
rors set for sharp convergence.
Compare with Fig. 19-1.
The amateur will find it to advantage to use the polarizing
filters set at 45 degrees from the vertical so that the normal Polar-
oid 3-Ddpectacles may be used for these polarized images, and for
Vectographs. This eliminates the necessity for two sets of spec-
tacles.
- The film is made with the reflector and projected normally.
This also provides a narrow picture, and it, too, may be optically
expanded or masked to proportion. The images are viewed by
prismatic viewers which eliminate the unwanted image by angu-
lar displacement. - The camera is operated at double speed and the projector is