All of the Colors tools are extensively described in the toolbox chapter, Section 5, “ Color Tools ”:
Section 5.1, “ Color Balance Tool ”
Section 5.2, “ Hue-Saturation Tool ”
Section 5.3, “ Colorize Tool ”
Section 5.4, “ Brightness-Contrast tool ”
Section 5.5, “ Threshold Tool ”
Section 5.6, “ Levels tool ”
Section 5.7, “ Curves Tool ”
Section 5.8, “Posterize Tool”