The two options are "Darker" and "Lighter." Lighter was the one selected already. Since I'm calibrating my TV to the equipment, I want to make sure that the equipment is mimicking the reference signal as much as possible. I need to know whether "Darker" is actually darkening the picture, or if "Lighter" is actually lightening the picture. Either is a modification of the original picture, so it matters to me to know the difference. So for instance, if "Darker" were darkening the picture, I'd choose "Lighter" and calibrate based on that setting.
Any help is appreciated :)