Thus, for all that it was an astonishing
breakthrough, the gun was still far from an
ideal photographic instrument as far as Marey
was concerned. For example, while it gave the
successive attitudes of the bird's wing he still
had to cut out each individual image, overlap
them and paste them along a horizontal axis on a
piece of paper if he wanted to measure the
wing's trajectory. This tedium almost effaced
the advantages of the camera. In addition, the
images produced by the gun had their drawbacks;
they were too small - about the size of postage
stamps - they lacked detail, there were too few
of them and they were too far apart.
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The gun did not provide the spatial
dimension of the movement; it did not supply an
impression of the exact path or distance traversed
within the defined time. This meant that the precise
speed of the flight could not be determined. Since
Marey had already been able to register such factors
with his graphing machines the photographic machine
had to be made to provide at least this minimum if
not more.
Marey's next steps were typical of
his approach to a problem. Usually he could be
counted on to see the elements in an instrument
which were successful and either re-arrange them to
overcome the instrument's limitations or use them as
the basis of a new instrument. Sometimes, if he
couldn't adapt the instrument to the subject, he
would adapt the subject to the instrument. In this
case he did both. Before tackling the camera proper,
he changed the subject matter. In the summer of 1882
he abandoned birds for the moment, to use a human
subject where the movements were less complex,
slower, and best of all, they took place in a
straight line and on the ground. Then, with a new
camera, he succeeded in finding a way of exposing to
the light one segment of the photographic plate at a
time and having each segment correspond to a
different phase of the movements of his subject. But
this time, he did it without moving the plate. |