Ozobrome 1905–ca. 1910, after 1913 renamed Raydex
Description
“In 1905 Thomas Manly (d. 1932) of London introduced the Ozobrome process,21 which was a modification of his earlier Ozotype, patented in 1898.22 The process was based on a carbon printing method proposed in 1873 by Auguste Marion (1835–1917) and the discovery, made in 1889 by Ernest Howard Farmer (1856–1944), that dichromates were reduced by contact with finely divided metallic silver in the presence of gelatin, which in turn caused the gelatin to become insoluble.23 The Ozobrome process differed slightly from the carbon process. The pigment paper (called Ozobrome Pigment Plaster) was not exposed to light through a negative but was squeegeed firmly to the surface of a wet gelatin silver bromide print immediately after it had been soaked in a sensitizing and bleaching bath (called Ozobrome Pigmenting Solution). A chemical reaction took place that simultaneously bleached the bromide print and hardened the pigmented gelatin in situ, in proportion to the amount of silver contained in the image. The bromide print was stripped, and the pigment paper was then squeegeed onto a sheet of transfer paper for development in hot water, where the unhardened gelatin was washed off (Manly 1907). The principal advantages of Ozobrome over carbon were that prints could be made without the direct action of light and without enlarged negatives.
[…]
In 1913 Samuel Manners (1871−1954) of London acquired the rights to the Ozobrome process and promoted it as a three-color process under he name Raydex (Coote 1993: 76) (Fig. 3.18). Raydex materials included pigment papers; two grades of bromide paper, fast and slow; sensitizing solution; transparent support; and temporary and final transfer papers. The process received good reviews and was thought to be the first ‘to bring the production of three color printing within the capacity of the ordinary amateur’ (Coe 1978: 104). Manners traveled to New York in 1925 to promote his process in the United States, only returning to England in 1928. Raydex materials remained available until the late 1920s.”
(Pénichon, Sylvie (2013): Twentieth Century Colour Photographs. The Complete Guide to Processes, Identification & Preservation. London, Los Angeles: Thames & Hudson, on pp. 99–100.)
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Pénichon, Sylvie (2013): Twentieth Century Colour Photographs. The Complete Guide to Processes, Identification & Preservation. London, Los Angeles: Thames & Hudson, p. 100.
Secondary Sources
Pénichon, Sylvie (2013): Twentieth Century Colour Photographs. The Complete Guide to Processes, Identification & Preservation. London, Los Angeles: Thames & Hudson, on pp. 99–100. View Quote
