The Joly colour process is an early

additive Additive may refer to: Mathematics * Additive function, a function in number theory * Additive map, a function that preserves the addition operation * Additive set-function see Sigma additivity * Additive category, a preadditive category with fin ...

colour photography Color photography (also spelled as colour photography in Commonwealth English) is photography that uses media capable of capturing and reproducing colors. By contrast, black-and-white or gray-monochrome photography records only a single channe ...

process devised by

Dublin Dublin is the capital and largest city of Republic of Ireland, Ireland. Situated on Dublin Bay at the mouth of the River Liffey, it is in the Provinces of Ireland, province of Leinster, and is bordered on the south by the Dublin Mountains, pa ...

physicist John Joly in 1894.

Description

Based on a method proposed in 1869 by

Louis Ducos du Hauron Louis Arthur Ducos du Hauron (8 December 1837 – 31 August 1920) was a French pioneer of color photography. Personal life He was born in Langon, Gironde and died in Agen. Photography After writing an unpublished paper setting forth his basic ...

in ''Les Couleurs en Photographie – Solution du Probleme'', the Joly colour process used a glass

photographic plate Photographic plates preceded film as the primary medium for capturing images in photography. These plates, made of metal or glass and coated with a light-sensitive emulsion, were integral to early photographic processes such as heliography, d ...

with fine vertical red, green and blue lines less than 0.1 mm wide printed on them. The plate acted as a series of very fine

filters Filtration is a physical process that separates solid matter and fluid from a mixture. Filter, filtering, filters or filtration may also refer to: Science and technology Computing * Filter (higher-order function), in functional programming * Fil ...

, in a similar way to the later

Paget process The Paget process was an early colour photography process patented in Britain in 1912 by G.S. Whitfield and first marketed by the Paget Prize Plate Company in 1913. A paper-based Paget process was also briefly sold. Both were discontinued in th ...

. To take a photograph, the filter screen was placed in the camera in front of an

orthochromatic In chemistry, orthochromasia is the property of a dye or stain to not change color on binding to a target, as opposed to ''metachromatic'' stains, which do change color. The word is derived from the Greek '' orthos'' (correct, upright), and chr ...

photographic plate, so that the light passed through the filter before striking the emulsion. After exposure, the plate was processed and contact-printed on another plate to make a positive black-and-white transparency. This was then placed in register with a viewing screen of the same type as used for exposure, to produce a limited-colour transparency that could be viewed by transmitted light. The Joly process was introduced commercially in 1895 and remained on the market for a few years. However, it was expensive and the commercially available emulsions of the time were not sensitive to the full range of the spectrum, so the final colour image could not achieve the look of "natural colour". A large collection of colour slides by John Joly, mainly of botanical subjects, are held by the

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Notes

References

* Photographic processes dating from the 19th century Audiovisual introductions in 1895 Irish inventions {{filmmaking-stub

Description

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References