Thames Colour Plate
Description
“Thames Colour products originated from a 1906 patent by Clare Livingston Finlay (d. 1936) and were introduced commercially in England by the Thames Colour Plate Company of London in 1908 (Fig. 2.10).15 Color screens were obtained by repeatedly coating, printing, and dying dichromated colloids in the following manner: a glass plate, coated with dichromated colloid, was exposed to light through a pattern plate, opaque but for a series of small circles placed at regular intervals. Under the action of light, the colloid became insoluble where it had been exposed. After being washed in warm water to eliminate nonhardened colloid, the plate was immersed in a green dye bath. The same operation (coating, exposure, development) was repeated for the color red. To obtain the blue portion of the screen, the plate was coated a third time with the dichromated colloid, and light was shone through the back of the plate, using the existing colored circles as a screen. After development in warm water, the plate was immersed in a blue dye bath (Mees and Pledge 1910). The final pattern of the screen was composed of green and red circles, with the space in between dyed blue. When Thames color screen products were first introduced in 1908, they were issued as a separate system with no viewing screen. In 1909 the product was also issued as a combined system for the direct production of positives by reversal processing. Thames Colour plates were about eight times faster than autochrome plates because of the greatly improved light transmission of their screen, but their pattern was much coarser. ‘Interesting though the Thames plates are, I must admit… that they have not the transparency and critical accuracy of the Autochrome, and that the linear form of the colored screen seems to produce a distinctly ‘liney’ effect, and at the same time fail to reproduce minute details, or faint shades to anything like the same degree,’ wrote Knowles (1910: 40) in his review of available screen plates. Thames plates remained on the market until around 1910 (Coe 1978: 57), when the company was taken over by the Paget Prize Plate Company (Dobrusskin 1998: 62).”
(Pénichon, Sylvie (2013): Twentieth Century Colour Photographs. The Complete Guide to Processes, Identification & Preservation. London, Los Angeles: Thames & Hudson, on pp. 30–31.)
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Pénichon, Sylvie (2013): Twentieth Century Colour Photographs. The Complete Guide to Processes, Identification & Preservation. London, Los Angeles: Thames & Hudson, p. 30.
Secondary Sources
Pénichon, Sylvie (2013): Twentieth Century Colour Photographs. The Complete Guide to Processes, Identification & Preservation. London, Los Angeles: Thames & Hudson, on pp. 30–31. View Quote
