ELEMENTARY STEREOGRAPHY 5be used. The simplest consists of a board with a raised border or
frame around three sides. (Fig. 1-2). Let us assume that the cam-
era to be used is a box camera three inches wide and five inches
- BOX CAMERA
0
%AS€ ING CAMERA FOR FOLD- FRONT viEwFig. 1-2. Simple sliding base for making stereograms with any
camera.long. A board of this size would just be covered by the camera. It
is desired that the camera be moved sidewise 2% inches. If we add
this to the width of three inches, we have 5% inches, so the base-
board will be cut 5x51/2 inches. This board should be from a half
to three-quarters inch thick.
Along the two five-inch sides and along one 5G-inch side, thin
strips of wood are nailed, rising perhaps an inch above the top
of the board.
It is of the greatest importance that the baseboard be cut ab-
solutely square, and that the two ends be accurately parallel.
Perhaps it should be stated that these terms of accuracy are
intended for the amateur workman. An errm of one degree,
while undesirable, is not too serious.
This board may be provided with a screw socket so that it may
be mounted upon a tripod. In any event, some means should be
provided for holding the board motionless during the two expo-
sures. Otherwise the care spent in making the board accurately
will be wasted.
MAKING THE Exposum-The board is attached to the tripod
and the camera aligned as in making an ordinary photograph,