Memoire on the Heliograph …by Joseph Nicéphore Niépce (1833).
The invention which I made and to which I gave the name “heliography” consists in the automatic reproduction, by the action of light, with their gradations of tones from black to white, of the images obtained in the camera obscura.
Quote taken from ;-
Kertesz, A (Not Known) Photohelios: Memoire on the Heliograph, Available at: http://photohelios-team.blogspot.co.uk/2009/02/memoire-on-theheliograph.html(Accessed: 02/12/2016).
Taken from ; –
Henry Ransom Centre (Not Known) Jospeh Nicephore Niece : The First Photograph, Available at: http://www.hrc.utexas.edu/exhibitions/permanent/firstphotograph/niepce/#top(Accessed: 02/12/2016).