Description

An unique copper printing block representing the Janssen’s photographic revolver and used in May 1875 in the newspaper La Nature.

An important precinema apparatus.

“Jules Janssen was permanently lamed by an accident in early childhood. He studied at the University of Paris, and in 1865 became professor of general science in the school of architecture. He was an enthusiastic observer of eclipses. In 1870, when Paris was besieged during the Franco-Prussian War, he fled the surrounded city in a balloon so that he could reach the path of totality of a solar eclipse in Africa. With his photographic revolver, Janssen travelled to Japan to record and observe the transit of the planet Venus across the face of the sun, on 8 December 1874. The photograph most needed by astronomers was that showing the precise moment when the outline of the planet first encroached on the sun’s disc. As that moment was unpredictable, a clockwork ‘revolver’ was devised to take a sequence, one of which would be the required image. The revolver took forty-eight exposures in seventy-two seconds on a daguerreotype disc; a process was no longer in general use, but ideal for the project – the metal plate ensuring an absence of halation (flare) that could have been a problem if a glass plate had been used – and a wet plate would in any case have been inconvenient to use in such a camera. With the sun as the source there was no shortage of light, so the ‘slow’ daguerreotype process was ideal. The images were of good quality. Two English expeditions also used apparatus as suggested by Janssen to record the transit of Venus. Janssen presented the photographic revolver to the Société Francaise de Photographie in 1875, and to the Académie des Sciences in April 1876, where he suggested that his apparatus might be used for the study of animal movements, especially those of birds, when materials sensitive enough to permit the very brief exposures necessary became available”

The present print block was used in La Nature dated 8 Mau 1875, so this is one of the very first representation of this device.

The printing block measures 82x145mm, it is in perfect condition.

An unique piece in the history of precinema.