CIE Division 8 - TC8-03: Survey of Gamut Mapping Papers

UGRA (1995)

The GMA suggested here is a combination of Methods A and B, briefly described by Schläpfer (1994) and is in fact a continuation of the same authorís work. Hue angle is not altered by this method and the first step is a uniform linear lightness compression. Chroma compression is then carried out by first calculating the hue angle dependent ratio k:
 


Here r and o signify the reproduction and original respectively. The gamut mapped chroma is the calculated using the following quadratic equation:
 


This equation changes chroma in a non?linear way when k < 1 and leaves original values unchanged when k = 1.
 

Last updated: 17 August 1999 by Jan Morovic