92 THREE-DIMENSIONAL PHOTOGRAPHY
liberately cast off the old burden of ridiculous rules and discuss
those common elements of techniques which affect the result.
You will not find a prohibition in the chapter, only a few sug-
gestions with an explanation of probable results if you do
so-and-so.
The camera is yours. You bought the film. If you wish to lay
the camera on its back and shoot the whole roll making empty
pictures of the room ceiling, that is your privilege. In fact if you
do the same thing outdoors you might get some interesting cloud
effects! You do whatever you wish with your camera. If you find
some of the disappointments foretold in this chapter, you will not
have wasted time and film because to the hearsay of this discussion
you will have added direct personal experience for which nothing
else can adequately be substituted.
By all means make experiments. Most useful additions to hu-
man knowledge have been made by skeptics who wished to prove
(or disprove) some current belief. There have been some highly
successful stereograms (and photographs as well) made by a de-
liberate violation of some widely recognized rule.
In any such discussion as this it is necessary to make decisions
as to what subjects are to be included, what to be ignored. Stereog-
raphy overlaps planar photography, and most of the purely tech-
nical aspects of both fields are identical. There is no room to
include all conventional photographic technique, and no reason
for so doing as it is a subject which has been repeatedly discussed
by a number of writers. At the same time there are some aspects
of conventional photography which are of such particular interest
to the stereographer that they must be discussed at length, as in
the two chapters which follow this. Therefore the points discussed
will, in many instances, be familiar ones; some will be new.
This discussion will, generally, assume that color film is being
used because color is one of the important elements of stereo.
It may be said, however, for the benefit of those who use mono-
chrome processes, that the negatives made should be rather soft,
that is fully exposed and not overdeveloped.
Color exposure, of course, permits little control through ex-
posure variation, but the effects of under and overexposure affect
stereo more adversely than in the case of planar photography,