The Joly colour process is an early

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process devised by

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physicist

John Joly John Joly FRS (1 November 1857 – 8 December 1933) was an Irish physicist and professor of geology at the University of Dublin, known for his development of radiotherapy in the treatment of cancer. He is also known for developing techniques to ...

in 1894.

Description

Based on a method proposed in 1869 by

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

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, 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 the ...

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