Heliography

[1] Niépce used the process to make the earliest known surviving photograph from nature, View from the Window at Le Gras (1826 or 1827), and the first realisation of photoresist[2] as means to reproduce artworks through inventions of photolithography and photogravure.

In 1816 he had limited success with light-sensitive paper coated with muriate (or chloride) of silver placed in a homemade camera obscura were conducted; impressions of views out of his workroom window.

[12][13] The process used was low in sensistivity; Helmut Gernsheim estimated the exposure time might be eight hours, while Marignier,[14] based on his attempts to recreate the technique, as well evidence from Niépce’s letters, considered three or more days more likely.

By viewing the plate at an appropriate angle the viewer sees the shadow areas reflecting dark in contrast to the lighter film of bitumen, producing a legible, if elusive, positive picture of buildings, a tree, and the landscape beyond.

[11] Daguerre’s high successful eponymous process, in the specific chemicals and materials used, thus emerged directly out of his partnership with Niépce, whose own discoveries, never fully realised, sank into relative obscurity.

[21] Although named “héliographie” by Niépce, in the later 19th century “heliography” was used generally for all “sun-printing;” with “heliographic processes” coining to mean specifically the reprographic copying for line, rather than continuous tone, images.