The Dascolor process was invented by Léon-Josse Dassonville (1887–1975), pioneer of the cinematographic industry in Belgium. Research has uncovered information on seven short subjects shot in Dascolor, of which four survive – all made between 1934 and 1936 – suggesting that the exploitation of the Dascolor process was limited to a modest amount of self-produced samples, while failing to find broader commercial success. 

Léon-Josse Dassonville was born in Namur, Belgium, on December 25, 1887. Colloquially called Josse, he was raised and schooled mostly in Paris, working at the Société Pathé until the outbreak of World War I in 1914. Serving in the cinematographic service of the Belgian army (SCAB), he was charged with filming on the frontline and capturing aerial footage. After the war, Dassonville returned to Saint-Gilles, Brussels, where, on October 16, 1919, he founded the company Établissements L.J. Dassonville, a laboratory for film development and printing that mostly delivered French-language intertitles for foreign silent films. When the laboratory burned down in March 1922, Léon-Josse, together with his brother Louis, constructed a modern film laboratory at rue Berthelot 135–141 in Forest, Brussels. There, Dassonville began his research into a natural color process. Between 1930 and 1936, he filed four patent applications. The first focused on the color printing process itself, and the second on the printing of the sound track simultaneously with the second color record. Two more patents, issued in 1932 and 1936, stated improvements to the process, including the expansion to a three-color system. 

On December 14, 1934, Dassonville registered the company Société Anonyme Dascolor, capitalized for 600,000 Belgian francs, intended for the exploitation of the Dascolor process (Anon., 1935a: p. 30). The color process was in use from the summer of 1934, until the outbreak of World War II, when its exploitation ceased. In a 1966 interview, Léon Josse Dassonville explained that under American law the Dascolor patents had fallen into the public domain for the duration of the war and that he was unable to claim royalties (Anon., 1969: p. 17). Asserting that “the Americans shot millions of meters of color film using the Dascolor process”, he decided to confine the lab's post-war activities solely to developing and printing. (Anon, 1969: p. 17–18 [author's translation from French])

From its first results, the Dascolor process was marketed as a decidedly “Belgian” invention (Anon., 1934: p. 8). The color process was hailed as a testimony to the entrepreneurial efforts of Belgian captains of industry like Dassonville, who, in times of economic crisis, still “care enough about the country's reputation to dare to create a new industry” (Anon., 1935b: p. 5 [author's translation from French]). Also, film subjects such as Le défilé du 21 juillet (1934), with its flag parade on the Belgian National Day, and Ce que nos yeux ne verront plus (1935), of the Brussels World Fair of 1935, used an appeal to national pride to attract patrons and spectators. On December 15, 1936, Belgian director Gaston Schoukens organized a gala evening in the prestigious Cinema de l'Ermitage in Paris, to present the best of Belgian film production to the French public, “who hardly knows it exists” (Anon., 1936 [author's translation from French]). On the program were feature films by reputed filmmakers Henri Storck and Charles De Keukeleire, and short color films by Dassonville. Technical advances to the Dascolor process were suggested in a competitive spirit, in an article in the trade magazine Revue belge du cinéma:

“Did we know that Dassonville, constantly perfecting the Dascolor process, would soon be at the same point as the Americans? From the two-color process he used until now, our compatriot is now moving into three-color – and the film clips presented in Paris will be a revelation.” (Anon., 1936: p. 9 [author's translation from French])

Unfortunately, the only information on films employing this new Dascolor process comes from a B/W 16mm print of Tervuren, musée du Congo belge (Hélène Schirren, 1939) which credits the trichrome Dascolor process in its opening titles.

On December 16, 1955, Léon-Josse Dassonville was awarded the Medal of Chevalier in the Order of Leopold II by the Belgian Union of Cinematographers. He died, aged 88, on September 14, 1975. At the end of 1989, the company L. J. Dassonville, now headed by Josse's oldest son Jacques, was put into liquidation, 70 years after its incorporation. At some point, the Dassonville family deposited four short films printed in Dascolor at the Cinémathèque royale de Belgique – Cinematek, Brussels: Ce que nos yeux ne verront plus, Jolis contes de fées, Small Fish Fry, and an unidentified reel subsequently catalogued as [Côte d'Azur]. The laboratory buildings in rue Berthelot in Forest, Brussels, are still standing today, although they have been converted into lofts and apartments.