Introduced by Kodak in the 1956, C-22 is an obsolete process for developing color film, superseded by the C-41 process in 1972 for the launch of 110 film and in 1974 for all other formats.
The development of the film material is carried out at temperatures of around 75°F (24°C), making the process incompatible with the more modern C-41 process, which uses a temperature of 100°F (38°C). C-22 uses Color Developing Agent 3, unlike C-41, which uses Color Developing Agent 4.
The most common film requiring this process is Kodacolor-X.
C-22 film can still (as of 2020) be developed in black and white.
References
"Kodak Camera Film". https://www.photomemorabilia.co.uk/Colour_Darkroom/Early_Kodak_CameraFilm.html#anchor12 ↩
"C-22 Film and Black and White Processing – the Analogue Laboratory". 15 February 2014. http://www.analoguelab.com.au/c-22-film-and-black-and-white-processing/ ↩
"Kodacolor-X 35mm Film Cartridge and Box". https://thedarkroom.com/old-rolls-film-developing/kodacolor-x-35mm-film-cartridge-and-box/ ↩