Assignment 1: Carbon Print Process

Carbon print process was first invented by Alphonse-Louis Poitevin in 1855. A modified carbon print process which utilized a paper support coated one one side with a pigmented-gelatin solution known as carbon tissue was developed for general use by Joseph Wilson Swan in 1864. In 1868 Swan sold the rights to his process to John Robert Johnson and Ernest Edwards, who established the Autotype Company which commercially sold materials for carbon printing. Carbon printing rose to popularity in the US and Europe throughout the19th and early 20th century though by the 1950s, it use had significantly diminished. 

• Poitevin mixed carbon powder into a mixture of gelatin and potassium dichromate while searching for a permanent photographic process . When paper is coated with this tinted gelatin-dichromate mixture, any exposed areas harden and become insoluble in water. When immersed in water, the non-exposed areas dissolves, only leaving the hardened mixture on the paper [1].

• Swan added a small amount of sugar to the mixture which produced a less brittle image layer when dried. Additionally, the coated paper was exposed under a negative and attached. facedown to a support. 

View from the Lawn, Dennicannibly
Vernon Heath (1870s)

A carbon print can be produced through either a single or double transfer process. 

• A single transfer process produces a reversed image

• A double transfer process was used "When printing from negatives that contained orientation-sensitive visual information" [2]. Here a sensitized sheet of carbon tissue is placed in contact with a negative and exposed to an ultraviolet light source. The negative is made with an emulsion side of the tissue. After exposure, separate the negative from the tissue and soak the latter underwater with a paper substrate at about 65 degrees F, for 45-50 seconds, and then squeegee the tissue with a temporary plastic support. This creates a sandwich effect: temporary support - carbon image -final paper substrate. Cover with a sheet of blotting paper, place a sheet of plate glass over the paper, and leave for 20-30 minutes. When dry, transfer to a tray of warm water and develop by washing away the insoluble pigmented gelatin that was included within the carbon tissue [3].

The carbon print process belongs to a category of pigment photographic processes that are notable for their long-term permanence, a problem that was associated with the use of silver-based photographic prints [4].Visual characteristics of carbon print images include:

• Reddish brown, dark brown, and black tones

• Improved sharpness of detail when compared to silver prints

• Features an even and linear distribution of tones from the highest lights to the deepest shadows [5].

• Surfaces can be matte, glossy, or a relief surface

• Darker areas (which feature higher concentration of gelatin) appear glossier than others [6].

Microscopic characteristics of carbon print images include:

• With a microscope, one can see the presence of large carbon particles or pigment clusters. These are irregularly distributed within lighter areas of the image [7].

Microscopic view of pigment clusters

• Edges of prints that are un-mounted can feature delamination or lifting of the pigmented gelatin layer

• Surface cracks can appear in the thickest parts of the gelatin layer on the print [8].

Prevention concerns with carbon prints are relatively limited. Carbon prints are considered to be chemically stable and most deterioration that occurs is caused by external damage. Overall, carbon print images can be very long lasting

• Light fading and yellowing are rather rare with carbon prints unlike silver-based images

• Images made with organic dyes can experience light fading due to the dyes' light sensitivity

• The conservation of prints "Made with pigments other than carbon black depends on the stability of their pigment mixture -not all pigments are as light stable as carbon black" [9].

Notable Users

• Alfred Stieglitz

Winter - Fifth Avenue
Alfred Stieglitz (1893)

• William James Stillman

The Acropolis of Athens
William James Stillman (1869)

[1]. Dusan C. Stulik & Art Kaplan, The Atlas of Analytical Signatures of Photographic Processes: Carbon, (Los Angeles: The Getty Conservation Institute), 13.
[2]. Stulik & Kaplan, The Atlas of Analytical Signatures of Photographic Processes, 12.
[3]. Ibid., 12.
[4]. Bertrand Lavedrine, Photographs of the past: Process and preservation (Los Angeles: The Getty Conservation Institute, 2009) 164.
[5]. Sandy King, “Carbon Transfer: Contemporary Printers,” Sandy King: Photography, 2008, http://sandykingphotography.com/resources/technical-writing/carbon-transfer-contemporary-printers.
[6]. Ibid., 14.
[7]. Ibid., 15. 
[8]. Lavedrine, Photographs of the Past, 167. 
[9]. Ibid., 167.