K-14 process

K-14 was the most recent version of the developing process for Kodak's Kodachrome transparency film before its discontinuation (the last revision having been designated Process K-14M). It superseded previous versions of the Kodachrome process used with older films (such as K-12 for Kodachrome II and Kodachrome-X).

The K-14 process differed significantly from its contemporary, the E-6 process, in both complexity and length. Kodachrome film has no integral color couplers; dyes are produced during processing (each color in a separate step) by the reaction of the color couplers with the oxidised developer.

Due to declining sales, Kodak discontinued production of all K-14 chemistry in 2009, concurrently with Kodachrome 64 film. Dwayne's Photo, in Parsons, Kansas, operated the last K-14 line in the world, discontinued sales on 30 December 2010;  the last roll was processed on 18 January 2011.

Steps
The cross-section of Kodachrome film consists of layers which are, from top-to-bottom: blue sensitive (of which the non-sensitized portions will be dyed yellow), yellow filter, blue-green sensitive (dyed magenta), blue-red sensitive (dyed cyan), acetate base, rem-jet anti-halation backing.

The blue-green and blue-red sensitive layers are primarily sensitive to green and red light, respectively, but are sensitive to blue light as well. The yellow filter layer is added to prevent blue light from penetrating to these layers during exposure.

The result is three different color records each with the appropriate dye, just like other color films. The original Kodachrome process in 1935 used dye bleaches and was a far more complex process; the dyes themselves were unstable and faded at high temperature. Although the formulae have changed over the years, the basic process steps have followed a similar pattern since the introduction of "selective re-exposure" Kodachrome in 1938.