“In 1894 Professor John Joly of Dublin patented a process for producing a screen of red, green and blue-violet lines by ruling them on a gelatin-coated glass plate. Joly used ruling machines of great accuracy, with drawing pens trailed across the plate producing lines less than 1/225 inch (0.1 mm) wide, in contact with each other, but not overlapping. Aniline dyes mixed with gum provided the colour inks. The ruled plates were varnished when they were dry. The screen plate was placed face to face with an orthochromatic plate in a plate holder, with the screen towards the lens. It was necessary to use a yellow filter over the camera lens, to correct the plate’s excessive blue sensitivity. The exposed plate was separated from the screen and developed. A black and white transparency was then made on a suitable plate, and this positive was bound up with another line screen, the two being very carefully registered so that the correct colour element was behind each line of the picture. The Joly process was introduced commercially in 1895, and was the first additive screen-plate process to appear on the market. It remained available for a few years, but the inadequate colour sensitivity of the negative plates then available limited its usefulness.”

(Coe, Brian (1978): Colour Photograph. The First Hundred Years 1840-1940. London: Ash & Grant, pp. Coe, Brian (1978): Colour Photography. The First Hundred Years 1840-1940. London: Ash & Grant, on pp. 46-48.)

Secondary Sources

Coe, Brian (1978): Colour Photography. The First Hundred Years 1840-1940. London: Ash & Grant, on pp. 46-48. View Quote

Hopwood, Henry Vaux (1915): Color cinematography. In: Henry Vaux Hopwood: Hopwood’s living pictures. Their history, photoproduction, and practical working. With classified lists of British patents and bibliography. London: The Hatton Press, new ed., rev. and enl. by R.B. Foster, pp. 253–273, on p. 260. View Quote

Lavedrine, Bertrand (1998): History and Technology of Colour Photographic Processes. In: Luciano Berriatúa et al.: Tutti i colori del mondo. Il colore nei mass media tra 1900 e 1930. = All the colours of the world. Reggio Emilia: Edizioni Diabasis, pp. 117-119, on pp. 117-118. View Quote

Pénichon, Sylvie (2013): Twentieth Century Colour Photographs. The Complete Guide to Processes, Identification & Preservation. London, Los Angeles: Thames & Hudson, on pp. 22–24 View Quote and on p. 66. View Quote