Joly Color Screen
Encyclopedia
The Joly Color process is an early additive
color photography
process devised by Dublin physicist John Joly
in 1894.
in Les Couleurs en Photographie - Solution du Probleme, the Joly Color 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 filters
, in a similar way to the later Paget process
.
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-color 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 color image could not achieve the look of "natural color".
A large collection of color slides by John Joly, mainly of botanical subjects, are held by the National Library of Ireland
.
Additive color
An additive color model involves light emitted directly from a source or illuminant of some sort. The additive reproduction process usually uses red, green and blue light to produce the other colors. Combining one of these additive primary colors with another in equal amounts produces the...
color photography
Color photography
Color photography is photography that uses media capable of representing colors, which are traditionally produced chemically during the photographic processing phase...
process devised by Dublin physicist John Joly
John Joly
John Joly FRS was an Irish physicist, famous for his development of radiotherapy in the treatment of cancer...
in 1894.
Description
Based on a method proposed in 1869 by Louis Ducos du HauronLouis Ducos du Hauron
Louis Arthur Ducos du Hauron was a French pioneer of color photography. He was born in Langon, Gironde and died in Agen....
in Les Couleurs en Photographie - Solution du Probleme, the Joly Color process used a glass photographic plate
Photographic plate
Photographic plates preceded photographic film as a means of photography. A light-sensitive emulsion of silver salts was applied to a glass plate. This form of photographic material largely faded from the consumer market in the early years of the 20th century, as more convenient and less fragile...
with fine vertical red, green and blue
RGB color model
The RGB color model is an additive color model in which red, green, and blue light is added together in various ways to reproduce a broad array of colors...
lines less than 0.1 mm wide printed on them. The plate acted as a series of very fine filters
Filter (optics)
Optical filters are devices which selectively transmit light of different wavelengths, usually implemented as plane glass or plastic devices in the optical path which are either dyed in the mass or have interference coatings....
, in a similar way to the later Paget process
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 early 1920s...
.
To take a photograph, the filter screen was placed in the camera in front of an orthochromatic
Orthochromatic
- Orthochromatic photography :Orthochromatic photography refers to a photographic emulsion that is sensitive to only blue and green light, and thus can be processed with a red safelight. The increased blue sensitivity causes blue objects to appear lighter and red ones darker...
photographic plate, so that the light passed through the filter before striking the emulsion. After exposure, the plate was processed and contact-printed
Contact print
A contact print is a photographic image produced from film; sometimes from a film negative, and sometimes from a film positive. The defining characteristic of a contact print is that the photographic result is made by exposing through the film negative or positive, onto a light sensitive material...
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-color 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 color image could not achieve the look of "natural color".
A large collection of color slides by John Joly, mainly of botanical subjects, are held by the National Library of Ireland
National Library of Ireland
The National Library of Ireland is Ireland's national library located in Dublin, in a building designed by Thomas Newenham Deane. The Minister for Arts, Sport & Tourism is the member of the Irish Government responsible for the library....
.