Print

Gum Dichromate Print, or Process

(Fr.: épreuve/ procédé à la gomme bichromatée; ~ sépiaphoto; ~ photo-sanguine)

Newer name for GUM-BICHROMATE PRINT, or PROCESS. The gum process is a DIRECT CARBON PROCESS that relies on the light-sensitivity of a DICHROMATED COLLOID, i.e., gum arabic and ammonium dichromate. It was invented by Alphonse Poitevin, in 1855, but remained largely dormant until it was revived, ca. 1894, by Rouillé-Ladevèze in Paris, who used formulas published in La Nature, in 1887.

Unlike the CARBON TRANSFER and FRESSON processes, gum does not provide sharp details and has always been reserved for pictorial/artistic use. The best known exponents of the process were Robert Demachy, Constant Puyo, Gertrude Käsebier, and Eduard Steichen. More information can be found in Luis Nadeau's Gum Dichromate and Other Direct Carbon Processes, from Artigue to Zimmerman, 1986. (Nadeau, Encyclopedia, p. xxx).

Venice. Gum print in sanguine color by I. Keene (or Kuehn, later changed to Keene?), ca. 1915. Image 118 x 168 mm Venice. Gum print in sanguine color by I. Keene (or Kuehn, later changed to Keene?), ca. 1915. Image 118 x 168 mm

Venice. Gum print in sanguine color by I. Keene (or Kuehn, later changed to Keene?), ca. 1915. Image 118 x 168 mm.

Detail of Poitevin's French patent 24,592 (Aug. 1855), which covered gum/carbon printing and collotype Detail of Poitevin's French patent 24,592 (Aug. 1855), which covered gum/carbon printing and collotype

Detail of Poitevin's French patent 24,592 (Aug. 1855), which covered gum/carbon printing and collotype.