“R. Berthon patented the use of a lens diaphragm with three apertures, covered respectively with red, green and blue-violet filters, and a sensitive surface on a support, the other side of which was impressed with hemi-spherical, transparent, refractive protuberances, which acted like microscopic lenses. There would thus be formed on the sensitive surface images of the three-field diaphragm. Or the colored filters of the diaphragm might be apportioned into a series of microscopical parallel transparent portions, then the lenticular forms might take the shape of semi-cylindrical ridges. The opaque striations of the diaphragm must be inversely proportional to the lengths of the fundamental wave of each colored filter; thus their number must be such that their linear projection on the sensitive film gives at least sixteen lines per millimeter in the red, nineteen in the yellow-green and twenty in the blue-violet. A positive might be made from the negative thus obtained, or the latter might be reversed and the positive viewed through the lens, an image in colors would then be seen or it might be projected.”
(Wall, E.J. (1925): The History of Three-color Photography. Boston: American Photographic Pub. Co., p. 667.)
Original Technical Papers and Primary Sources
Berthon, Rodolphe (1910): Colour Photography. In: The British Journal of Photography, 57, pp. 421-423.
Dr. N. (1937): Linsenraster. In: Film-Kurier, 183, 2.8.1937, Serie “Farb-Film-Fibel”. (in German)
Eggert, John (1932): Kurzer Überblick über den Stand der Farbenkinematographie. In: John Eggert and Arpad von Biehler: Bericht über den VIII. Internationalen Kongress für wissenschaftliche und angewandte Photographie, Dresden 1931, Leipzig: J. A. Barth, pp. 214–222, on pp. 220–221. (in German)
Evans, Ralph Merrill; Hanson, W.T., Jr.; Brewer, W. Lyle (1953): Principles of Color Photography. New York: Wiley, pp. 292-293.
Friedman, Joseph Solomon (1945): History of Color Photography. Boston: The American Photographic Publishing Company, pp. 222-225.
Mees, C. E. Kenneth (1937): The Development of the Art and Science of Photography in the Twentieth Century. In: Journal of the Society of Motion Picture Engineers, 28,1, pp. 3–20, on p. 13.
Wall, E.J. (1925): The History of Three-color Photography. Boston: American Photographic Pub. Co., p. 667.
F.P. 399 762, May 1908, Perfectionnements aux procédés photographiques trichromes.