Chromogenic print

A chromogenic print, also known as a C-print or C-type print, a silver halide print, or a dye coupler print, is a photographic print made from a color negative, transparency or digital image, and developed using a chromogenic process. They are typically made of three layers of gelatin containing a light-sensitive emulsion of silver halide; each layer contains a different dye coupler of subtractive color such that together, when developed, a full-color image is formed.

History

Figure from patent US2113329A, issued by Kodak, describing a photographic color process using color-coupling substances, such as the ones used in a chromogenic print.

Developing color by oxidizing a developer was first suggested by German chemist Benno Homolka who, in 1907, successfully developed water-insoluble dyes on a latent image by oxidation of indoxyl and thio-indoxyl, producing indigo-blue and red dye respectively. He noted these developers could create beautiful photographic effects.

The potential of developer oxidation products in a full-color photographic process, however, was first conceived by another German chemist, Rudolf Fischer [de], who in 1912 filed a patent describing a chromogenic process to develop both positives and negatives using indoxyl and thio-indoxyl-based color developers on a light-sensitive silver halide emulsion. The following year he filed a patent listing introducing the idea of a dye coupler: a compound spread throughout the emulsion layer that couples with the oxidized developer to form a dye. Fischer's patent goes on to list several developers and dye couplers which have historically been used in Agfachrome and are still in use today in Fujichrome Velvia, Provia and Ektachrome. In spite of this, Fischer never created a successful color print due to his inability to prevent the dye couplers from moving between the emulsion layers.

This first solution to this problem was devised by Agfa workers Gustav Wilmanns and Wilhelm Schneider. Their solution was to utilize dye couplers that are made of long hydrocarbon chains and ending with either a carboxylic or sulfonic acid group: The long hydrocarbon chains anchored the couplers in place, while the acid group on their ends enabled them to form micelles which are easily scattered in gelatin while also loosely tethering to it.:698 Agfa patented both the developer for this print and its photographic process, and promptly developed and released Agfacolor Neu in 1936, the world's first chromogenic print, a color print film that could be developed using a transparency.:698 Agfa developed a negative-to-positive chromogenic color film by 1939, which was possible to develop directly on the film's companion paper. While available to the German film industry at the time, the film was never publicly commercialized.

Kodak too worked to solve the issue of the dye couplers movement, and came up with a different solution. For their dye couplers, they used hydrocarbon chains that were significantly shorter than Agfa's and weren't ionically soluble, and then suspended them within droplets of water in the gelatin layers of the print.:698 In 1942, Kodak released Kodacolor, the first publicly available negative-to-positive chromogenic color film.

These prints were a much simpler-to-develop and cheaper counterpart to the color photography alternatives at the time. This shift meant chromogenic color prints became increasingly popular in amateur photography, and by the 1960s they overtook black and white printing in the amateur photofinishing market.

In 1955, Kodak introduced a chromogenic paper named "Type C", which was the first color negative paper Kodak sold to other labs and to individual photographers. Although the paper's name was changed to "Kodak Ektacolor Paper" in 1958, the term "Type-C Print" persisted, and became a popular name for negative-to-positive chromogenic prints which is still in-use today. "Type-R Print", meanwhile, became the name of the reversal film counterpart.

Notwithstanding their commercial success in the amateur and professional market, chromogenic prints weren't considered a medium for fine-art photography up to the 1970s. Pioneers in the fine-art usage of chromogenic prints in particular, and of color photography as a whole, include photographers such as Ernst Haas, which was profiled by the Museum of Modern Art in its first exhibition of color photography in 1962.:257 Other pioneers in this field include William Eggleston:251 and Stephen Shore, among many others. Their works had elevated chromogenic prints to the preferred medium for contemporary photography by the 1990s.

Chromogenic prints made from negatives became obsolete with the release of chromogenic digital prints, which have become the most common photographic print today.

Development of prints

Chromogenic processes are characterized by an oxidation of the developer by metallic silver, followed by a coupling reaction between the oxidized developer and the different dye couplers to produce the colors that make up the full-color image:

Following the film's exposure, the 3 layers of a light-sensitive silver halide emulsion form a latent image. A developer is then added, which gets oxidized by regions of metallic silver. Subsequently, this oxidized product couples with the different dye couplers in each of the layers, forming different dyes. By using dye couplers of 3 subtractive colors, their coupling with the oxidized developer produces a full-color image. This coupling reaction also anchors the created dyes in the emulsion, allowing the print to be bleached and fixed: To better preserve the print, the remaining metallic silver is bleached by a strong oxidizer, returning it to its previous state as a silver halide. The silver halide, meanwhile, is solubilized by a fixer, allowing the silver ions to be removed from the emulsion layers. The exposure of a chromogenic print may be accomplished with a traditional photographic enlarger using color filters to adjust the color balance of the print.

The print's name is derived from the chromogenic coupling reaction between the dye coupler and the oxidized developer.

Chromogenic print today

Chromogenic prints, like most color photographic prints, are developed using the RA-4 process. As of 2017, the major lines of professional chromogenic print paper are Kodak Endura and Fujifilm Crystal Archive. Plastic chromogenic "papers" such as Kodak Duratrans and Duraclear are used for producing backlit advertising and art.[citation needed]

Reversal film prints

A reversal film chromogenic print, also known as a Type-R print, is a positive-to-positive photographic print made on reversal-type color photographic paper.

Fujifilm, Kodak, and Agfa have historically manufactured paper and chemicals for the R-3 process, a chromogenic process for making Type-R prints. As of 2008, all of these companies have ceased to produce Type R paper, although Fujifilm still has some stocks remaining.[citation needed]

Another positive-to-positive process was Ilfochrome, formerly Cibachrome, in use until 2012. This is sometimes also referred to as a Type-R process. Ilfochrome was a dye destruction process, with materials, processing, and results quite different from the R-3 process.

Digital chromogenic prints

A digital chromogenic print, sometimes known as digital Type-C print, Lambda print or LightJet print, is a chromogenic print made from a digital file rather than a negative, and exposed using digital exposure systems such as the Durst Lambda, Océ LightJet and ZBE Chromira. The LightJet and the Lambda both use RGB lasers to expose light-sensitive material to produce a latent image that is then developed using conventional silver-based photographic chemicals. The Chromira uses light-emitting diodes (LEDs) instead of lasers. All of the aforementioned printers utilize ICC color profiles to achieve color and density accuracy and also to correct paper sensitivity errors. The same technology can also be used to produce digital silver gelatin bromide black and white prints.

References

  1. ↑ Tate. "C-print – Art Term". Tate. Retrieved 2020-08-16.
  2. 1 2 3 Gawain, Weaver; Long, Zach (2009). "Chromogenic Characterization: A Study of Kodak Prints 1942-2008" (PDF). Topics in Photographic Preservation. 13. American Institute for Conservation of Historic and Artistic Works: 67–78.
  3. 1 2 3 "Definitions of Print Processes - Chromogenic Print". Santa Fe, New Mexico: Photo-Eye Gallery. Archived from the original on May 21, 2022. Retrieved October 15, 2026.
  4. 1 2 "Chromogenic prints". L’Atelier de Restauration et de Conservation des Photographies de la Ville de Paris. 2013. Retrieved November 12, 2017 – via Paris Photo.
  5. ↑ Fenstermaker, Will (April 27, 2017). "From C-Print to Silver Gelatin: The Ultimate Guide to Photo Prints". Artspace. Retrieved November 13, 2017.
  6. ↑ Homolka, Benno (February 1907). "Experiments on the Nature of the Latent Image and of the Negative Image" (PDF). The British Journal of Photography. 54: 136–138 – via Barbara Flueckiger.
  7. ↑ US patent 1055155A, Fischer, Rudolf, "Process of making photographs in natural colors.", issued March 4, 1913
  8. ↑ US patent 1102028A, Fischer, Rudolf, "Process of making colored photographs.", issued June 30, 1914
  9. ↑ Waller, David; Hinz, Zbigniew J.; Filosa, Michael (2000). "I. Printing and imaging technologies - Chapter 3: Dyes used in photography, 2. Conventional photographic dyes". In Freeman, H. S.; Peters, A. T. (eds.). Colorants for non-textile applications (1st ed.). Amsterdam: Elsevier. pp. 61–64. ISBN 9780444828880 – via Google Books.
  10. ↑ Triedman, Karen (2015). Colour: The Professional's Guide: Understanding and Mastering Colour in Art, Design and Culture. London: Ilex Press. p. 144. ISBN 9781781573624 – via Google Books.
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  12. ↑ US patent 2163166A, Wilmanns, Gustav; Schneider, Wilhelm & Wendt, Bruno, "Photographic developer", published May 27, 1936, issued June 20, 1939, assigned to Agfa Ansco Corp.
  13. ↑ US patent 2179239A, Wilmanns, Gustav; Bitterfeld, Kreis & Schneider, Wilhelm et al., "Color photography", published April 10, 1935, issued November 5, 1939, assigned to Agfa Ansco Corp.
  14. ↑ Alt, Dirk (2011). "'Front in Farbe': Color Cinematography for the Nazi Newsreel, 1941-1945". Historical Journal of Film, Radio and Television. 31 (1): 43–60. doi:10.1080/01439685.2011.552680.
  15. ↑ Hirsch, Robert (2014). "Chapter two - A concise history of color photography: Chromogenic negative film". Exploring Color Photography: From Film to Pixels (6, illustrated, revised ed.). CRC Press. p. 31. ISBN 9781317911159 – via Google Books.
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  17. 1 2 Touchetter, Amy (June 8, 2017). "A Quick History of Color Photography (for Photographers)". envato tuts+. Retrieved April 15, 2019.
  18. 1 2 Wilhelm, Henry (Spring 2014). Contemporary Analog and Digital Color Photographic Prints: Dye and Pigment Print Process Descriptors, Naming Conventions, Dating, and Permanence Characteristics (PDF). American Institution for Conservation 2014 annual conference – via American Institute for Conservation of Historic and Artistic Works.
  19. 1 2 3 Read, Shirley (2013). "Chapter 17: Printing for Exhibition by Mike Crawford - Print types: C type print". Exhibiting Photography: A Practical Guide to Displaying Your Work (2nd ed.). United Kingdom: Taylor & Francis. ISBN 9781136102530. Retrieved November 15, 2017 – via Google Books.
  20. ↑ Dafoe, Taylor (November 22, 2017). "Stephen Shore's MoMA Retrospective Takes You on a Trip Through Photography's Recent History". Artnet news. Artnet. Retrieved April 7, 2019.
  21. ↑ Theys, Ronald D; Sosnovsky, George (5 February 1997). "Chemistry and Processes of Color Photography". Chemical Review. 97 (1): 83–132. doi:10.1021/cr941191p.
  22. ↑ Lavédrine, Bertrand (2003). A Guide to the Preventive Conservation of Photograph Collections. Getty Conservation Institute. p. 48. ISBN 978-0892367016. Chromogenic prints... are produced by the exposure of a negative... the color balance is adjusted by using color filters on the enlarger.
  23. ↑ "Pikto Paper". PIKTO. Retrieved October 28, 2017.
  24. ↑ "What is a digital C Type print?". January 24, 2017. Retrieved October 28, 2017.
  25. ↑ "Digital Chromogenic Prints". Genesis Imaging. Retrieved October 28, 2017.
  26. ↑ "Chromira". zbe. Retrieved October 28, 2017.