Subtractive two color Technicolor (actually two distinct processes, Technicolor II with its cemented prints and the Technicolor III process which introduced dye transfer) is without doubt the best known two color process. Here is Bryony Dixon on the Technicolor fragments (the best known of the two color subtractive systems) discovered at BFI, as first presented at CiF 2018 by Jane Fernandes:
James Layton (who will return to Color in Film 2020 with a great program of MoMA color rarities!) explains the two-color Technicolor process in this beautiful video from Eastman Museum’s Technicolor 100 series.
Like Technicolor, two color Kodachrome employed gelatin hardening to translate photographic density into dye uptake. However, in this system, dye would preferentially be taken up by the soft gelatin, where in Technicolor the latter would be “etched” away with hot water, leaving a hardened gelatin relief image to be dyed up afterwards. This beautiful example, courtesy George Eastman Museum and Kodak, was restored in 2009 by Selznick School graduate and Haghefilm fellow Sabrina Negri.
Multicolor was an early two color system employing double coated film to combine two emulsions / color records on one strip of film, employing the same chemical toning approach used in applied color, to translate a black and white image into a colored one. In this example from the Timeline of Historical Film Colors, the typical Iron Blue color can be see separately in the perforation area, particularly the edge code, and by the image’s edges.
Multicolor was folllowed by Cinecolor, which was employed into the late 1940s as a cheaper alternative to the groundbreaking full color, ‘Glorious’ Technicolor process. Animation, of course, facilitated the most control over color design within a limited palette, and one of the most important series in this regard was by former (and, again, later!) Disney pioneer, Ub Iwerks. On Cartoon Research, his series of ‘Comicolor’ cartoons has been evaluated by animation expert, Jerry Beck.
Cinecolor may be the only two color system that was used in the 16mm format also. Here is the leader of a Castle films ‘headliner’ (i.e. abridged, mute) edition of one of the Iwerks Cinecolor cartoons, evidencing one of the two thick, dull-looking (due to chemical toning) emulsions and what is apparently markings from the blue source separation film source, courtesy of 16mm film collector Bram Blijleven.
Development of two color systems wasn’t limited to Hollywood. An important early German example came from film production giant, Ufa. Explore the Ufacolor system here on the Timeline of Hirstorical Film Colors.
Even less than for other two-color systems is known about the Dutch/German Sirus process, in no small part due to lack of original sources. At Colour in Film 2020, the latest results on historically and chemically analyzing, and indeed distinguishing between, two color systems such as Ufacolor and Sirius will be shared by Anke Mebold (DFF), student speaker Sreya Chatterjee and Ulrich Ruedel (HTW Berlin).