Gum Bichromate

Gum Bichromate Process and Print

History:

Motiv aus Pommern,
by Hugo Henneberg
Gum bichromate print, 1902.
The Metropolitan Museum of Art.

Gum bichromate, or gum dichromate as it is also known, is a photographic printing process invented in the early days of photography when, in 1839, a Scottish inventor Mungo Ponton discovered that dichromates are light sensitive. William Henry Fox Talbot, inventor of the calotype process, later found that colloids such as gelatin and gum arabic became insoluble in water after exposure to light. Alphonse Poitevin, a French chemist, added carbon pigment to the colloids in 1855, creating the first carbon print. In 1858, John Pouncy used colored pigment with gum arabic to create the first color images; thus, the first true gum bichromate print.   

Dame mit Pfingstrosen (Emma Kuhn-Katsung - wife),
by Heinrich Kuhn. 
Gum bichromate print, ca. 1900.
George Eastman House Collection.

This process was used by fine art photographers, popular up until the 1920's; however, alternative photographic artists have revived this process stretching the boundaries with watercolor variations.  As mentioned, any variation of pigmentation can be used as long as it is water soluble, and most materials receiving the emulsion can be used such as various types of paper, wood, and plastics.  The gum print can be resensitized and reprinted using different colors if so desired; by applying multiple colors, the variations are unlimited.  

Portrait of a woman - profile,
by Elias Goldensky (American, 1867-1943).gum bichromate print, ca. 1915.George Eastman House.

Gum bichromate images will feature a slightly fuzzy, or soft, blended lines look to it, which may resemble a drawing from a crayon or charcoal.  Unless the gum print is framed, an observer will see the brush strokes where the gum emulsion was applied along the edges of photograph.  Most gum prints, even some produced today, may look like a painting from a glance rather than a photo print.  The finished prints are generally stable, and surviving prints from the late 19th century are usually in excellent shape.   

The Pool--Evening:A Symphony to a Race and to a Soul,
by Steichen, Edward, 1879-1973.
Gum bichromate-platinum print, 1898.
ARTstor Slide Gallery.

Process:

• A photographic emulsion is mixed using gum arabic, and ammonium or potassium dichromate.
• Water soluble pigment(s) are mixed into the now light sensitive emulsion.
• The emulsion is coated onto a piece of paper smoothly using a fine wide brush applying even horizontal and vertical strokes. 
• The coated paper is set to dry for several hours in the dark.
• A negative is placed over the dry emulsion and sandwiched under glass.
• The print is exposed to ultraviolet light for a few minutes.
• The print is then washed under running cold water to wash off the gum emulsion in order to develop image. An additional soaking in clean water for further development; additional colored tones may be added to enrich and enhance image.   

Rhine Street, Krefeld, by Scharf, Otto.
Gum bichromate, 1898.
ARTstor Slide Gallery.

References:


Coe, Booth, and Mark Haworth-Booth. A Guide to Early Photographic Processes. The Victoria and Albert Museum, 1983. 


Lavedrine, Bertrand. Photographs of the Past. Los Angeles: The Getty Conservation Institute, 2009. 

Ritzenthaler, Mary L, Diane Vogt-O'Connor, and Mary L. Ritzenthaler. Photographs: Archival Care and Management. Chicago: Society of American Archivists, 2006.

Wikipedia, Gum Bichromate entry, retrieved Feb 25, 2013.
http://en.wikipedia.org/wiki/Gum_bichromate

www.artstor.org

www.billymabrey.com 

What is a Gum Bichromate Print?, YouTube,
 http://youtu.be/RoiajbLFsRE

St Pauls Photography - Gum Bichromate, YouTube, 
http://www.youtube.com/watch?v=1cTL6NDTh9o&feature=share&list=PLFCA0312707ABA522