Chromogenic process

In analog photography, a process for developing multilayer films with color couplers is referred to as a chromogenic or dye-forming process or dye development .

The color couplers can be located

• in the film layers ( Agfacolor process , C-41 process , Eastman Color process and Perutz process ) or
• in the developer liquids ( Kodachrome process ).

The color couplers react with the oxidation product of the color developer to form yellow, magenta and blue-green dyes in the three subtractive primary colors. After development, the dyes resulting from the color couplers form the color image by subtractive color mixing .

As a rule, at least three superimposed layers , each sensitized for blue , green or red with embedded color couplers, are used.

History and Development

The chromogenic process was developed by Rudolf Fischer and Hans Sigrist at the Neue Photographische Gesellschaft in Berlin-Lankwitz and patented in 1911/1912 .

See also

• Film development
• Subtractive Color Mixing and Additive Color Mixing
• Chromolytic process

literature

• Otto Krätz: 7000 years of chemistry . DW Callway publishing house, Munich, 1990

Web links

• - Color photography (lecture by Petra Ring as part of the exercises in lectures with demonstrations - Physical Chemistry SS 2000 ( Memento from April 1, 2006 in the Internet Archive ), Didactics of Chemistry, University of Bayreuth, Germany, as of January 26, 2001)