Color theory is a complex subject dealing with how color represented, interpreted by programs, generated by output devices, and perceived by humans. The articles here detail how Photoshop handles color theory.
“Color modes are the basis for the representation of a pixel's color value. Between different...Color mode
“Color correction is the process of applying adjustments to an image to resolve variations in...Color correction
“A color profile determines how an output device (i.e. monitor, printer) will interpret the color...Color profile