blue sensitive film

SUBJECT AREA: Photography, film and optics

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The son of a tax collector, Ducos du Hauron began researches into colour photography soon after the publication of Clerk Maxwell's experiment in 1861. In a communication sent in 1862 for presentation at the Académie des Sciences, but which was never read, he outlined a number of methods for photography of colours. Subsequently, in his book Les Couleurs en photographie, published in 1869, he outlined most of the principles of additive and subtractive colour photography that were later actually used. He covered additive processes, developed from Clerk Maxwell's demonstrations, and subtractive processes which could yield prints. At the time, the photographic materials available prevented the processes from being employed effectively. The design of his Chromoscope, in which transparent reflectors could be used to superimpose three additive images, was sound, however, and formed the basis of a number of later devices. He also proposed an additive system based on the use of a screen of fine red, yellow and blue lines, through which the photograph was taken and viewed. The lines blended additively when seen from a certain distance. Many years later, in 1907, Ducos du Hauron was to use this principle in an early commercial screen-plate process, Omnicolore. With his brother Alcide, he published a further work in 1878, Photographie des Couleurs, which described some more-practical subtractive processes. A few prints made at this time still survive and they are remarkably good for the period. In a French patent of 1895 he described yet another method for colour photography. His "polyfolium chromodialytique" involved a multiple-layer package of separate red-, green-and blue-sensitive materials and filters, which with a single exposure would analyse the scene in terms of the three primary colours. The individual layers would be separated for subsequent processing and printing. In a refined form, this is the principle behind modern colour films. In 1891 he patented and demonstrated the anaglyph method of stereoscopy, using superimposed red and green left and right eye images viewed through green and red filters. Ducos du Hauron's remarkable achievement was to propose theories of virtually all the basic methods of colour photography at a time when photographic materials were not adequate for the purpose of proving them correct. For his work on colour photography he was awarded the Progress Medal of the Royal Photographic Society in 1900, but despite his major contributions to colour photography he remained in poverty for much of his later life.

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SUBJECT AREA: Photography, film and optics

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In 1841, while studying at Cambridge, Sutton became interested in photography and tried out the current processes, daguerreotype, calotype and cyanotype among them. He subsequently settled in Jersey, where he continued his photographic studies. In 1855 he opened a photographic printing works in Jersey, in partnership with L.-D. Blanquart- Evrard, exploiting the latter's process for producing developed positive prints. He started and edited one of the first photographic periodicals, Photographic Notes, in 1856; until its cessation in 1867, his journal presented a fresher view of the world of photography than that given by its London-based rivals. He also drew up the first dictionary of photography in 1858.

In 1859 Sutton designed and patented a wideangle lens in which the space between two meniscus lenses, forming parts of a sphere and sealed in a metal rim, was filled with water; the lens so formed could cover an angle of up to 120 degrees at an aperture of f12. Sutton's design was inspired by observing the images produced by the water-filled sphere of a "snowstorm" souvenir brought home from Paris! Sutton commissioned the London camera-maker Frederick Cox to make the Panoramic camera, demonstrating the first model in January 1860; it took panoramic pictures on curved glass plates 152×381 mm in size. Cox later advertised other models in a total of four sizes. In January 1861 Sutton handed over manufacture to Andrew Ross's son Thomas Ross, who produced much-improved lenses and also cameras in three sizes. Sutton then developed the first single-lens reflex camera design, patenting it on 20 August 1961: a pivoted mirror, placed at 45 degrees inside the camera, reflected the image from the lens onto a ground glass-screen set in the top of the camera for framing and focusing. When ready, the mirror was swung up out of the way to allow light to reach the plate at the back of the camera. The design was manufactured for a few years by Thomas Ross and J.H. Dallmeyer.

In 1861 James Clerk Maxwell asked Sutton to prepare a series of photographs for use in his lecture "On the theory of three primary colours", to be presented at the Royal Institution in London on 17 May 1861. Maxwell required three photographs to be taken through red, green and blue filters, which were to be printed as lantern slides and projected in superimposition through three projectors. If his theory was correct, a colour reproduction of the original subject would be produced. Sutton used liquid filters: ammoniacal copper sulphate for blue, copper chloride for the green and iron sulphocyanide for the red. A fourth exposure was made through lemon-yellow glass, but was not used in the final demonstration. A tartan ribbon in a bow was used as the subject; the wet-collodion process in current use required six seconds for the blue exposure, about twice what would have been needed without the filter. After twelve minutes no trace of image was produced through the green filter, which had to be diluted to a pale green: a twelve-minute exposure then produced a serviceable negative. Eight minutes was enough to record an image through the red filter, although since the process was sensitive only to blue light, nothing at all should have been recorded. In 1961, R.M.Evans of the Kodak Research Laboratory showed that the red liquid transmitted ultraviolet radiation, and by an extraordinary coincidence many natural red dye-stuffs reflect ultraviolet. Thus the red separation was made on the basis of non-visible radiation rather than red, but the net result was correct and the projected images did give an identifiable reproduction of the original. Sutton's photographs enabled Maxwell to establish the validity of his theory and to provide the basis upon which all subsequent methods of colour photography have been founded.

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SUBJECT AREA: Photography, film and optics

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Waterhouse spent most of his career in the Indian Army. In 1861–2 he was commissioned to photograph the tribes of central India, and over the next few years visited many parts of the subcontinent. In November 1866, after working for five months in the Great Trigonometrical Survey learning the process of photozincography (an early photomechanical process used chiefly for map making), he took charge of photographic operations at the Surveyor-General's office in Calcutta, a post he held until retiring in 1897. During this time he developed many improvements in the photomechanical methods used for reproduction in his office. He also experimented with methods of colour-sensitizing photographic materials, experimenting with eosine dye and publishing in 1875 the fact that this made silver halide salts sensitive to yellow light. He also discovered that gelatine dry plates could be made sensitive to red and infra-red illumination by treatment with alizarine blue solution.

He continued his researches upon his retirement and return to England in 1897, and made a special study of the early history of the photographic process. His work on dye sensitizing brought him the Progress Medal of the Royal Photographic Society, and the Vienna Photographic Society awarded him the Voigtländer Medal for researches in scientific photography. One invention often erroneously attributed to him is the Waterhouse stop, the use of a series of perforated plates as a means of adjusting the aperture of a photographic lens. This was described in 1858 by a John Waterhouse, being his only contribution to photography.

SUBJECT AREA: Photography, film and optics

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Coming from a prosperous family, Niepce was educated in a Catholic seminary and destined for the priesthood. The French Revolution intervened and Niepce became an officer in an infantry regiment. An attack of typhoid fever in Italy ended his military career, and he returned to France and was married. Returning to his paternal home in Chalon in 1801, he joined with his brother Claude to construct an ingenious engine called the pyréolophore, which they patented in 1807. The French Government also encouraged the brothers in their attempts to produce large quantities of indigo-blue dye from wood, a venture that was ultimately unsuccessful.

Nicéphore began to experiment with lithography, which led him to take an interest in the properties of light-sensitive materials. He pursued this interest after Claude moved to Paris in 1816 and is reported to have made negative images in a camera obscura using paper soaked in silver chloride. Niepce went on to experiment with bitumen of judea, a substance that hardened on exposure to light. In 1822, using bitumen of judea on glass, he produced a heliograph from an engraving. The first images from nature may have been made as early as 1824, but the world's earliest surviving photographic image was made in 1826. A view of the courtyard of Niepce's home in Chalon was captured on a pewter plate coated with bitumen of judea; an exposure of several hours was required, the softer parts of the bitumen being dissolved away by a solvent to reveal the image.

In 1827 he took examples of his work to London where he met Francis Bauer, Secretary of the Royal Society. Nothing came of this meeting, but on returning to France Niepce continued his work and in 1829 entered into a formal partnership with L.J.M. Daguerre with a view to developing their mutual interest in capturing images formed by the camera obscura. However, the partnership made only limited progress and was terminated by Niepce's death in 1833. It was another six years before the announcement of the first practicable photographic processes was made.

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