The fusil photographique (1)
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Muybridge’s visit, however, seemed to galvanize Marey
into action and, understanding that photography offered
him the means he needed to expand the graphic method, he
spent the months that followed honing the camera into a
scientific instrument that would render a visible
expression for the passage of time simultaneously with a
picture of the moving object in space. His first
experiments were with a photographic gun that made 12
sequential images a second on a rotating glass disk.
The source of this instrument was the photographic
revolver created in 1873 by his colleague, the
astronomer Pierre-César Jules Janssen (1824-1907), and
used by him to record the transit of Venus across the
sun on the 8th of December, 1874. Janssen, who wanted to
photograph the moment when planetary and solar disks
came into contact with each other, had the idea of
taking a series of images so that "the photographic
image of this contact would necessarily be included in
the series and at the same time it would show the
precise instant when the phenomenon occurred." *
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| Marey's and Janssen's guns worked on the
same principle: a light sensitive plate rotated
intermittently behind a lens; the plate stopped long
enough for part of its surface to be exposed to light,
and then moved on; as the next, unexposed segment of the
plate moved towards the lens, a slotted disk shutter
blocked the light, and when this new segment reached the
lens, the plate stopped and the shutter let the light
through to it. |
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* Janssen, « Présentation d'un spécimen
de photographies d'un passage artificiel de Vénus, obtenu
avec le revolver photographique »,
CRAS, 79, 6 juillet 1874 :
p. 6-7.
Janssen had published a description of the principles of
his method in " Méthode pour obtenir photographiquement
l'instant des contacts avec les circonstances physiques
qu'ils présentent",
CRAS, 76, 17 mars 1873, p.
677. From
this, an English prototype was made by Dallmeyer in
April, 1874, before Janssen made his definitive model in
France in July. A full description of the apparatus was
then published by Janssen in the Bulletin de la Société
Française de Photographie, April, 1876, the same year in
which Janssen was admitted to the society. (Janssen
became president of the Society in 1899, taking over
from Marey who had been elected president in 1893.) |
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