All of the Colors tools are extensively described in the toolbox chapter, Del 5, “Fargeverktøya”:
Del 5.2, “Color Balance”
Del 5.3, “Hue-Saturation”
Del 5.4, “Colorize”
Del 5.5, “Brightness-Contrast”
Del 5.6, “Threshold”
Del 5.7, “Levels”
Del 5.8, “Curves”
Del 5.9, “Posterize”
Del 5.10, “Desaturate”