William Henry Fox Talbot - Inventor of the negative-positive technique

Immediately upon his return to England, Talbot turned his attention to the problem Working with a tiny two-and-a-half-inch-square camera, Talbot sensitized a piece of writing paper and exposed it for over an hour. The delicate lilac-tinted sheet of paper he then removed from his camera is today acclaimed as the worlds first negative. The image was not more than one inch square, but its creator proudly wrote in the space beside it that it was so sharp "the squares of glafs [sic] about 200 in number could be counted, with the help oi a lens.

The renowned British astronomer Sir John Herschel coined the words "negative" and "positive" to describe the process. Herschel, intrigued by the search to find a simple way to render lasting images, had contributed a vital discovery of his own: that sodium thiosulfate (hypo) was the best fixing agent for making photographs permanent.

Talbot's invention of the negative-positive technique made possible the creation of multiple prints from a single negative, thus changing the course of photographic history. Without this technique, modern photography as we understand it today would be impossible. On January 31 1839 Talbot announced his discovery to the world in a paper he read before the Royal Society in London. Three weeks later he followed it with a second paper in which he described all of the technical details necessary to duplicate his
experiments.

Five years later he achieved another historic first. He published a collection of his own photographs in an exquisite and rare book he called The Pencil of Nature

Today it is one of the prizes most sought after by the ever-growing community of eager photography collectors, who hail it as the world's first photographic book. In the almost century and a half since the publication of The Pencil of Nature, a virtual avalanche of photography books has been sold in countries worldwide, serving a market of avid readers and an even more avid following of photographers. Whether amateur or professional, most strive for -and some succeed in achieving - the sublime standards set by one of photography's illustrious pioneers, William Henry Fox Talbot.

William Henry Fox Talbot (11 February 180017 September 1877) was a British inventor and a pioneer of photography. He was the inventor of calotype process, the precursor to most photographic processes of the 19th and 20th centuries. He was also a noted photographer who made major contributions to the development of photography as an artistic medium. His work in the 1840s on photo-mechanical reproduction led to the creation of the photoglyphic engraving process, the precursor to photogravure. Talbot is also remembered as the holder of a patent which, some say, affected the early development of commercial photography in Britain. Additionally, he made some important early photographs of Oxford, Paris, and York.Hugh Murray, Nathaniel Whittocks bird's-eye view of the City of York in the 1850's

Talbot was known by his second name Henry, rather than William. It is commonly assumed that "Fox Talbot" is an unhyphenated double-barrelled surname. However, Fox was his mothers maiden name and was not passed on to his children. Some historians have therefore argued that he should be referred to as "Talbot" rather than "Fox Talbot". Nevertheless, although he signed his name as "H.F. Talbot" as well as "H. Fox Talbot", he was most often referred to by his contemporaries, including his mother, as "Mr Fox Talbot" or "Mr H Fox Talbot". "H Fox Talbot" was also the style he chose for his most important publications, including The Pencil of Nature.

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The Talbot effect is a near-field diffraction effect first observed in 1836 by Henry Fox Talbot.H. F. Talbot 1836 "Facts relating to optical science" No. IV, Philos. Mag. 9 When a laterally periodic wave distribution is incident upon a diffraction grating,

its image is repeated at regular distances away from the grating plane. The regular distance is called the Talbot length, and the repeated images are called self images or Talbot images. Furthermore, at half the Talbot length, a self image also occurs, but phase-shifted by half a period (the physical meaning of this is that it is laterally shifted by half the width of the grating period). At smaller regular fractions of the Talbot length, sub-images can also be observed. At one quarter of the Talbot length, the self image is halved in size, and appears with half the period of the grating (thus twice as many images are seen). At one eighth of the Talbot length, the period and size of the images is halved again, and so forth creating a fractal pattern of sub images with ever decreasing size, often referend as Talbot carpet.William B. Case, Mathias Tomandl, Sarayut Deachapunya and

Markus Arndt 2009 "Realization of optical carpets in the Talbot and Talbot-Lau configurations" Opt. Exp. 20966

Lord Rayleigh showed that the Talbot effect was a natural consequence of Fresnel diffraction and that the Talbot length can be found by the following formula:Lord Rayleigh 1881 "On copying diffraction gratings and on some phenomenon connected therewith" Philos. Mag. 11

z_T=\frac{2a^2}{\lambda}

where a is the period of the diffraction grating and \lambda is the wavelength of the light incident on the grating.

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William Henry Fox Talbot [Hardcover]

William Henry Fox Talbot [Hardcover]

William Henry Fox Talbot [Hardcover]