FIRST PERMANENT CAMERA PHOTOGRAPHS - 1825-26. Photographic history has recently been rewritten following the discovery of what is now considered to be the world's oldest photograph. The image, a reproduction of a 17th century Dutch print, predates by one year Frenchman Nicéphore Niépce's previous heliogravure of the view from his window at Le Gras, regarded until now as the earliest surviving photographic image.
In the early 1800s, Joseph Nicephore Niepce experimented with lithography at his home near Chalon, France. Nicephore explored light-sensitive varnishes, trying to find a coating that would record drawings after exposure to light. In 1816, he took photos using a camera and paper sensitized with silver chloride. He had some success, but was dissatisfied because the images were reversed (negatives) and could not be made permanent. He had tried to produce a positive print, but was unable to do so. He did find that nitric acid helped to preserve images for a while, but would not prevent eventual fading. Niepce's breakthrough came in 1822 when he made a permanent image using a camera obscura. After exposing coated pewter plates to a camera image, he used the vapors from heated iodine crystals to darken the silver and heighten contrast. The method would later inspire Louis Daguerre's successful mercury vapor development process. Within a few years the two inventors would become partners. Niepce was able to produce a copy of an engraving by passing light through the original photo onto a piece of glass coated with bitumen of Judea, a type of asphalt. Light hardens bitumen of Judea, so when Niepce washed the plate with solvent only the unexposed portions were removed, leaving a permanent image on the plate. He named this process “heliography” or sun-writing. He made numerous heliographs during the next several years and continued his attempts to produce a permanent camera image. In 1825, he was successful.
