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