Coloring of individual frames by the use of very fine brushes. The process was previously applied to lantern slides. Any water based translucent dye was suited for the process, most often the coloring was done with acid dyes.
In contrast to tinting, toning is not the simple immersion of a film into a dye bath but involves a chemical reaction converting the silver image. In this reaction the neutral silver image in the emulsion of the positive film is replaced by one consisting of colored metal compounds. These were usually iron ferrocyanide (Prussian Blue) for blue, copper ferrocyanide for red/brown, silver sulfide for sepia or rarely uranium ferrocyanide for reddish brown. Toning had been used in still photography before. But since film was projected on the screen it required translucent toning compounds.
For tinting, the positive print is immersed into a variety of dye baths, scene by scene. To this end, the print has to be cut into the corresponding fragments and reassembled after the dyeing process. The dye homogeneously attaches over the entire image’s gelatin including the perforation area. Usually synthetic dyes were dissolved in a weak acid solution to form a chemical bond with the gelatin.
Pénichon, Sylvie (2013): Twentieth Century Colour Photographs. The Complete Guide to Processes, Identification & Preservation. London, Los Angeles: Thames & Hudson, p. 87.
Source: Pénichon, Sylvie (2013): Twentieth Century Colour Photographs. The Complete Guide to Processes, Identification & Preservation. London, Los Angeles: Thames & Hudson, p. 235.
Pénichon, Sylvie (2013): Twentieth Century Colour Photographs. The Complete Guide to Processes, Identification & Preservation. London, Los Angeles: Thames & Hudson, p. 10.
"Du Hauron invented his Chromographoscope in 1874. It could be used either as a camera or an additive viewer." Source: Coote, Jack H. (1993): The Illustrated History of Colour Photography. Surbiton, Surrey: Fountain Press.
„Film orthochromatique (film négatif Pathé Standard)“ (orthochromatic stock). Source: Didiée, L. (1926): Le Film vierge Pathé. Manuel de développement et de tirage. Paris: Pathé.
Pénichon, Sylvie (2013): Twentieth Century Colour Photographs. The Complete Guide to Processes, Identification & Preservation. London, Los Angeles: Thames & Hudson.
Source: Coe, Brian (1978): Colour Photography. The First Hundred Years 1840-1940. London: Ash & Grant.
Loïe Fuller (FRA 1905, Anonymous). Credit: BFI National Archive. Photographs of the hand colored nitrate print by Olivia Kristina Stutz, ERC Advanced Grant FilmColors.
Photomicrograph (20x) of a Joly screen. Credit: Courtesy of George Eastman House, International Museum of Photography and Film.
Credit: Illustration by Sarah Steinbacher, Multimedia & E-Learning-Services, University of Zurich. Source: Ede, François (1994): Jour de fête ou la couleur retrouvée. Cahiers du Cinéma: Paris.
Hongarije (FRA 1926, Anonymous). Credit: EYE Film Museum. Photographs of the tinted, toned and stencil colored nitrate print by Olivia Kristina Stutz, ERC Advanced Grant FilmColors.
Salomé (USA 1922, Charles Bryant). Credit: George Eastman Museum. Photographs of the tinted, toned and Handschiegl nitrate print by Barbara Flueckiger.
Source: D.R.P. 98,799, Dec. 17, 1897
Pénichon, Sylvie (2013): Twentieth Century Colour Photographs. The Complete Guide to Processes, Identification & Preservation. London, Los Angeles: Thames & Hudson, p. 25.