K14 is the proprietary chemical process developed and used exclusively by Kodak for processing Kodachrome colour reversal film, producing the finished colour transparencies - commonly known as slides - for which Kodachrome became world famous. The K14 process was a highly complex and technically demanding colour development procedure that set Kodachrome apart from virtually every other colour film on the market and had significant practical implications for photographers throughout the film's long commercial life.
Unlike most other colour films, which incorporate colour forming dye couplers within the emulsion layers of the film itself, Kodachrome was manufactured without any dye couplers in the emulsion. Instead, the colour dyes were introduced during the development process itself, with the K14 chemistry adding the appropriate cyan, magenta, and yellow dyes to each of the film's three light sensitive layers in a precise and carefully sequenced series of chemical steps. This approach, while enormously complex, allowed Kodachrome to achieve the exceptionally fine grain structure, rich colour saturation, and outstanding archival stability for which it became renowned.
The complexity of the K14 process meant that it could not be carried out by photographers themselves or in standard independent processing laboratories. Kodachrome film had to be sent to one of Kodak's own authorised processing facilities, where specialist equipment and rigidly controlled chemical procedures were maintained to ensure consistent and accurate results. This arrangement, while convenient in the early decades of colour photography, became increasingly impractical as the network of K14 processing laboratories gradually contracted over the years.
Kodak discontinued Kodachrome film in 2009, and the last remaining K14 processing laboratory in the world - Dwayne's Photo in Kansas, USA - ceased processing Kodachrome in December 2010, bringing the K14 process to a close after more than seven decades. The discontinuation marked the end of an era in colour photography, as Kodachrome and its unique K14 process had played an immeasurable role in shaping the visual history of the twentieth century.