Editing Henry Fox Talbot (section)

== Photographic inventions ==
[[File:Latticed window at lacock abbey 1835.jpg|thumb|left|upright|Latticed window at [[Lacock Abbey]], August 1835. A positive from what may be the oldest existing camera negative.<ref>[http://foxtalbot.dmu.ac.uk/letters/transcriptDate.php?month=1&year=1839&pageNumber=8&pageTotal=11&referringPage=0 A contemporary letter by Talbot] states that his January 1839 Royal Institution exhibit included "...various pictures, representing the architecture of my house in the country ... made with the Camera Obscura in the summer of 1835." A basis for naming this famous image as ''the'' oldest among the surviving camera negatives of similar date is not apparent.</ref>]]

Talbot invented a process for creating reasonably light-fast and permanent photographs that was the first made available to the public; however, his was neither [[View from the Window at Le Gras|the first such process invented]] nor the first one publicly announced.<ref>[[Jennie Boddington|Boddington, Jennie]] & State Library of Victoria (1989). The new art : photographs by William Henry Fox Talbot (1800–1877), La Trobe Collection, State Library of Victoria : Fox Talbot and the invention of photography. State Library of Victoria, [Melbourne, Vic.]</ref>

Shortly after [[Louis Daguerre]]'s invention of the [[daguerreotype]] was announced in early January 1839, without details, Talbot asserted priority of invention based on experiments he had begun in early 1834. At a Friday Evening Discourse at the [[Royal Institution]] on 25 January 1839, Talbot exhibited several paper photographs he had made in 1835. Within a fortnight, he communicated the general nature of his process to the Royal Society, followed by more complete details a few weeks later. Daguerre did not publicly reveal any useful details until mid-August, although by the spring it had become clear that his process and Talbot's were very different.

Talbot's early "salted paper" or "photogenic drawing" process<ref>Album of Photogenic Drawings (1839-1840) (in Italian : ''[https://www.metmuseum.org/art/collection/search/268303 Album di disegni fotogenici])'' by William Henry Fox Talbot British & (likely) Sebastiano Tassinari (metmuseum.org)</ref><sup>,</sup><ref>{{Cite web |title=Talbot's Processes - Photographic Processes Series - Chapter 3 of 12 |url=https://www.youtube.com/watch?v=v2zXypdzB8A |access-date=2024-04-23 |website=www.youtube.com| date=3 August 2018 }}</ref> used writing paper bathed in a weak solution of ordinary table salt ([[sodium chloride]]), dried, then brushed on one side with a strong solution of [[silver nitrate]], which created a tenacious coating of very light-sensitive [[silver chloride]] that darkened where it was exposed to light. Whether used to create shadow image [[photogram]]s by placing objects on it and setting it out in the sunlight, or to capture the dim images formed by a [[Lens (optics)|lens]] in a [[Camera obscura|camera]], it was a "printing out" process, meaning that the exposure had to continue until the desired degree of darkening had been produced. In the case of camera images, that could require an exposure of an hour or two if something more than a silhouette of objects against a bright sky was wanted. Earlier experimenters such as [[Thomas Wedgwood (photographer)|Thomas Wedgwood]] and [[Nicéphore Niépce]] had captured shadows and camera images with silver salts years before, but they could find no way to prevent their photographs from fatally darkening all over when exposed to daylight. Talbot devised several ways of chemically stabilizing his results, making them sufficiently insensitive to further exposure that direct sunlight could be used to print the negative image produced in the camera onto another sheet of salted paper, creating a positive.