The 150th anniversary of photography

Abstract

Abstract One hundred and fifty years ago last summer Joseph Nicéphore Niépce succeeded in obtaining a camera picture on a polished pewter plate, sensitized with bitumen of Judea. This material has the unusual property of hardening in light (not blackening like silver salts) but its light sensitivity is small. Niépce needed 8-10 h exposure in sunshine. He named his invention “heliography”. After dissolving the unexposed parts of the picture in oil of turpentine and rinsing the plate, there remained, without the need for any other fixing, a permanent bitumen image of the light drawing, the shadows being indicated by the bare pewter plate. To avoid a lateral reversal of the view, Niépce had employed a prism in front of his achromatic lens. He had obtained both components from the Parisian optician Chevalier when he purchased his first professional camera in January that year. After using glass, lithographic stone and zinc for previous experiments, he had ordered the pewter plates in May 1826.