Three-Dimensional Photography - Principles of Stereoscopy

APPENDIX B

STEREO GLOSSARY

There is nothing very difficult or different about stereo, but it

is a distinct branch of photography and has its own terminology.

These specific words and phrases are not intended to confuse,

they simply make it possible to say some specific thing in a few

words and without which it would require many more words to

make the same statement, and in less satisfactory manner.

Although you will soon become familiar with these terms, it is

convenient to have a glossary available while you are still un-

familiar with the subject. This glossary is offered for reference.

It is far from complete, but it does include the most useful words

common to stereo but less familiar outside the field.

As you progress you will meet many terms not included here,

but for the most part they will

vanced phases of the subject.

American stereoscope.-The common par-
lor or Holmes version of the Brewster
stereoscope. Also Mexican stereoscope.
AnagZyph.-A stereogram of two superim-
posed images in which the images are
blocked to their respective eyes, so each
eye sees only its own proper image. The
original form was the bichrome in which
the images are printed in two comple-
mentary colors and viewed through cor-
respondingly colored filters. A half cen-
tury ago the process of using polarized
light instead of color was patented, and
today is favored over the color type for
projection. In motion picture work, alter-
nate frames are dyed in complementary
color and the film run at double speed to
produce the alternate anaglyph. Both bi-
chrome and polarized types are now in
use. Books and magazines, for practical
reasons, are usually illustrated in bi-
chrome anaglyphs.
Anaglyphic restoration.-Reconverting an
anaglyph to its original form of two sep-
arate photographs to be viewed in a con-
ventional stereoscope.
Autostereo plate.-An obsolete plate with
a parallax grid on the back, used €or
making direct parallax stereograms. Re-
versal processing.
Autotransposer.-Either a printing frame

be terms dealing with more ad-

or machine in which provision is made

for transposition by simply pulling two

levers.

Auxiliaries, stereo visual.-Factors in ster-

eo vision which enhance the stereo relief

but which are not essential to stereo

vision. The two most important are the

effects of perspective and overlapping of

distant objects by those nearer.

Base.-The stereo base is the distance be-

tween homologous optical points, usually

the optical axes of the camera, but also

applied to the separation of viewer lenses

and at times to human interpupillary.

Box stereoscope.-A stereoscope in the

form of an enclosed box as contrasted

with the skeleton form of Holmes. Stand-

ard in Europe.

Brewster, Sir David.-Probably the true

inventor of stereoscopic reproduction, al-

though the claims of Wheatstone are also

favored by some. Brewster was the first to

point out the overwhelming importance

of the subjective in stereo. He also in-

vented the prismatic stereoscope (semi-

lenticular) which is properly known by

his name, but often called Holmes, Mexi-

can, American and the like. These are

only one type of Brewster construction.

C. T. meter.-Color temperature meter.

See Color meter.

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