A subtractive color process called kodachrome made color
photography practical.
It was perfected by Leopold Mannes (1899-1964) and Leopold
Godowsky (1900-1983), two musicians and amateur
photographic researchers.
Their collaboration with Eastman Kodak scientists led to the
introduction of Kodachrome in 1935. Kodachrome was a single
sheet of film coated with three layers of emulsion, each
sensitive to one primary color (red, green and blue). A single
exposure produced a color image.