# Dictionary of National Biography, 1885-1900/Claudet, Antoine François Jean

​CLAUDET, ANTOINE FRANÇOIS JEAN (1797–1867), photographer, was born at Lyons on 12 Aug. 1797, and, after receiving a good commercial and classical education, entered at the age of twenty-one the office of his uncle, M. Vital Roux, banker, who a few years afterwards placed him at the glass works of Choisy-le-Roi as director, in conjunction with M. G. Bontemps. Eventually Claudet came to London, and in 1829 opened a warehouse at 89 High Holborn for the sale of French glass, but in 1833 describes himself as the owner of a sheet glass, glass shade, and painted glass warehouse. He took George Houghton into partnership in 1837, and the latter for many years continued to manage the business. In 1833 Claudet invented the machine now generally used for cutting cylindrical glass, and for this invention he received the medal of the Society of Arts in 1853. Daguerre's great discoveries were announced in January 1839; in the following August, on the purchase of his invention by the French government, the new discovery was published to the world. Daguerre secured a patent in England for his process, and Claudet, becoming possessor of a portion of this patent, commenced about 1840 the practice of daguerreotype portraiture in the Adelaide Gallery, London, where his studio remained for many years. He zealously devoted himself to photography, perfecting known processes and inventing new ones. He first obtained vastly increased sensitiveness by using chloride of iodine instead of iodine alone. In 1847, discussing the properties of solar radiation modified by coloured glass media, he made a bold attempt to lay the foundation of a more complete theory of the photographic phenomena, and he was rewarded by the publication of his paper in the 'Philosophical Transactions' (1847, pp. 253-62), and by his subsequent election, 2 June 1853, as a fellow of the Royal Society. At this time the collodion process had supplanted the method of Daguerre, and Claudet was one of the first to adopt it. He assisted Sir Charles Wheatstone in the early application of the stereoscope to photography. The reports of the British Association during twenty years bear testimony to the ingenuity and originality of his inventions. His dynactinometer, his photographometer, his focimeter, his stereomonoscope, his system of unity of measure for focusing enlargements, his system of photosculpture, and other results of his experimental researches, are familiar to all students of the photographic art. He removed to 107 Regent Street, London, in 1851, and in 1858 was appointed photographer in ordinary to the queen. In his later years he invented 'A self-acting focus equaliser, or the means of producing the differential movement of the two lenses of a photographic optical combination which is capable, during the exposure, of bringing consecutively all the planes of a solid figure into focus without altering the size of the various images superposed.' After this, and in the same year, he had a correspondence with his collaborator, Sir David Brewster, who held that the most perfect photographic instrument is a single lens of least dispersion, least aberration, and least thickness. Claudet realised these views with a small topaz lens which reached with equal distinctness every plane of the figure. He was the author of upwards of forty papers, communicated from 1841 to 1867 to the Royal and other philosophical societies, and to photographic and philosophical publications in England and France. He received awards of eleven medals, including the council medal of the Great Exhibition of 1851 ; but acting on juries, on other great occasions he was excluded from participation in the prizes. In 1863 he was made a chevalier of the Legion of Honour. He died at his residence in Regent's Park, London, on 27 Dec. 1867. Only a few weeks after his death, 23 Jan. 1868, his photographic premises in Regent Street were destroyed by fire, when the only negative of Claudet's portrait was entirely consumed. His widow, Julia, died at Brighton on 30 Oct. 1881, aged 80.
Claudet was the author of a small brochure entitled 'Du Stéréoscope et de ses applications à la Photographie,' Paris, 1853.
G. C. B.