xii INTRODUCTIONan excellent planar picture simply ruins the characteristic value
of the stereogram. A new form of composition must be used, in
fact it must largely be devised in the future, if we are to have
esthetically pleasing results.
The planar photographer need have no extensive knowledge of
the principles of human vision to produce pleasing pictures, but
the stereographer can never approach the ultimate possibilities
of his art unless he has a working knowledge of the principles of
stereoscopic vision. For that reason, it has been necessary to in-
clude somewhat more theory in this volume than should be found
in the usual photographic reference book. Much of this theory,
however, is subject to highly interesting experimental demon-
stration, so that the process of working through the theoretical
considerations will be found to provide quite as much pleasurable
activity as actually making the stereogram. The theoretical con-
siderations have in so far as possible been incorporated with the
practical procedure. Not only does this make the theory easier
to grasp, but at the same time it simplifies the process of acquiring
stereoscopic skill.
Stereography is now undergoing a revival of popularity, and
we are convinced that once the amateur has experienced the
deep pleasure of seeing his photographs in the incredible realism
of three dimensions, he will thereafter give to stereography his
full enthusiasm.