Dufaycolor was an additive three-color screen process based on a technique originally developed for photographic glass plates by Louis Dufay in France. Dufay’s original screens employed a uniformly structured mosaic pattern of four colors, which he patented in 1908 as Diopticolore – he began manufacturing glass plates under the name Dioptichrome the following year. In 1917, Dufay applied the same process to positive photographic film using his new company name, Société Versicolor. 

As manufacturers of paper and film products, including cellulose acetate wrapping material, the owners of Spicer Ltd in Cambridgeshire, England, were aware of the burgeoning market in photographic cellulose acetate “safety” film. Seeking to expand their product range, and with a keen interest in investing in the quest for a commercially viable natural color film process, Spicer Ltd purchased the rights to the line-screen process from Louis Dufay in 1926. The company provided initial financial backing with technical guidance provided by employees A. Dykes Spicer and S. R. Wycherley (Carson, 1934: p.19). T. Thorne Baker, an engineer with expertise in photochemical processes, who had previously worked with Louis Dufay in France, and engineer Charles Bonamico were hired to carry out extensive research and development in the manufacturing of the color screen process, which they called the réseau – French for network or grid. That same year, Dufay, Baker and Bonamico shot several thousand feet of negative in the south of France on 8-lines per mm réseau and showed the prints at the Pavilion Theatre in London. (Cornwell Clyne, 1951: p.20)

In spring 1931, an improved 20-lines per mm Dufaycolor 35mm motion picture film was demonstrated at the Royal Society in London, and again, later that year, at the British Kinematograph Society. In 1932, another demonstration was made at the Film Society in London and, that same year, Ilford Ltd and Colortone Holdings Ltd joined Spicer Ltd to form Spicer-Dufay (British) Ltd. Production of the film stock was divided between Spicer’s Sawston, Cambridgeshire, factory where the réseau was made, and Ilford’s Brentwood, Essex, factory where the light-sensitive emulsion was applied. The following year, the company changed its name to Dufaycolor Ltd, and also registered Dufaycolor, Inc. in the United States.

On April 20, 1934, the first public demonstration of 35mm and 16mm Dufaycolor was held at the Savoy Hotel in London. Initially, Spicer’s primary interest was in producing a viable color solution for the motion picture industry, particularly as a competitor to Technicolor – but realizing a viable negative-positive, scalable process proved technically challenging. However, as a 16mm direct-positive reversal process, Dufaycolor was enthusiastically embraced by amateur filmmakers upon its UK launch in the late summer of 1934. Kodacolor and Vitacolor had enjoyed some success among amateur filmmakers since the late 1920s but had largely fallen out of use by 1934. Both processes required additional, sometimes costly, equipment to create and project the color, but Dufaycolor’s réseau meant that the color was integral to its film stock, so no proprietary accessories were required. A 50ft-reel cost 21 shillings (one guinea – a pound and one shilling), which included processing.

W. H. Carson, vice-president of Dufaycolor, Inc., presented the process to the Society of Motion Picture Engineers in Atlantic City, NJ, in spring 1934. But, due to delays with securing US licensing, it wasn’t until spring 1935 that 16mm Dufaycolor hit the US market – coinciding with the launch of Kodachrome. While Kodachrome’s subtractive process offered the amateur greater ease of use, problems with the dye couplers in its first three years – causing a distinctive red cast – initially allowed Dufaycolor to claim a portion of the amateur market. Its practicality, and relative affordability, made Dufaycolor popular with amateur filmmakers and in 1937 9.5mm Dufaycolor reels and Pathéscope cassettes were introduced in Europe.

Dufaycolor 8mm is mentioned in several issues of International Photographer throughout the summer of 1936, and the authors of Silver by the Ton note that there may have been plans to introduce 8mm, but there is no evidence that it was ever produced for the retail market. Some sample frames of unslit double 8mm are held in the Film Frame Collection at the Seaver Center, Los Angeles, CA, and the contact information on the storage envelope – Film Specialists in El Monte, California – matches the company mentioned in International Photographer, but the exact nature of the connection is unknown. In 2015, a poorly slit double 8mm home movie was discovered in a private collection and subsequently donated to the University of Southern California’s HMH Moving Image Archive, but otherwise, there is no evidence that 8mm Dufaycolor was manufactured and sold commercially. 

In 1937, T. Thorne Baker moved to New York to work as technical consultant at Dufaycolor, Inc. (Kinematograph Yearbook, 1937: p. 307) Adrian Klein, later Cornwell-Clyne, was hired by, what was now known as, Dufay-Chromex (the company had merged the previous year with Chromex, a holding company for the takeover of British Cinecolor [Street, 2012: p.270]) to oversee research and development and to act as spokesperson for the Dufaycolor process – promoting it for commercial use. During this time, a new laboratory for product development and processing was opened at Thames Ditton, Surrey, England.

During World War II, Dufay-Chromex turned its Sawston-based factory over to the war effort, pausing research and production of photographic film. Postwar, it became clear that the future of color motion picture film was in subtractive processes. Production of film for stills photography – both color and B/W – continued for a few years. The 1949 edition of the Dufaycolor Data Book contains an extensive list of Dufaycolor distributors around the world, but any mention of Dufaycolor for the amateur filmmaker had all but disappeared. Operations at the factory finally ceased in 1955.