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74 REPORT OF COMMISSION VII
and mounted on stands permitting the handling of smaller precisions measuring
scales under the loupe, are especially suitable for quick two-dimensional measur-
ing. Loupes which magnify about 3, 6 and 10 times, should also be included in
the equipment.
The measuring work in single photos is chiefly carried out with accurate
measuring scales in a color, which owing to its contrast to the various grey
tones of the photos, facilitates the reading.
Precision pantographs of a smaller type are very suitable for drawing
sketches for interpretation reports based on reconnaissance photos. The in-
struments should permit accurate and precise adjustments of all desired circum-
stances of transfer between 1:10 and 1:1. The tolerance of accuracy should be
+0.2 mm.
As far as possible, reconnaissance photos should be studied in good light
which preferably should be evenly spread across the whole surface of the photo.
It is desirable that experiments be made to produce more effective and appro-
priate sources of lighting for photo-interpreters.
Among instruments still desired, should be specially mentioned a device
for easily and accurately determining beach slopes or terrain gradients,
Furthermore, development of a method for interpreting three-dimensional
projected aerial views and a more reliable method of determining beach and
terrain trafficability are desirable improvements.
In their work, the interpreters must have access to instructive, clear and
concise keys and guides, and special reports on various special subjects. See
TEACHING.
PHOTOGRAPHIC LABORATORY EQUIPMENT, EMULSIONS, ETC.
The laboratories for the photo-interpreting service must be well equipped
with material for reproduction, enlarging, reducing and contact printing, All
of this concerns work with negatives from the small photo size up to 9.5" X9.5"
(24 X24 cm.). Besides these, certain laboratories have at their disposal a machine
for making duplicate negatives, as well as multi-printers.
Projection apparatus for various sized photos must also be included in the
equipment.
All lenses of the apparatus must be of very high quality. This is extremely
important for the results of the interpretation. Improved reproducing apparatus
for field use is desired.
In this connection, it should be noted that speed in the work and sharpness
in the photo details are essential.
In accordance with the preceding, the demands regarding the emulsions are
high speed and fine grain. It is also desirable that a quick working, fine grained
developer be produced.
A special type of aero film is desirable, which will register the slight fading
effects on vegetation such as grass, etc., to facilitate the detection of diggings
and mine fields which have been well hidden by means of peat.
OTHER TECHNICAL EQUIPMENT
Speed, accuracy and reliability are factors of the greatest importance in
military intelligence. Each new method or invention, which can contribute to
improved results is received with satisfaction. The greatest interest was evi-
denced in the news of the first successful experiment with Air to Ground trans-
mitted photographs, made on 15 August 1949 by the U. S. Air Force. A vertical
from this occasion, reproduced in the Photographic Journal of April 1950, shows
half-tones and details very well rendered.
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