Many of the tools inside of Photoshop use various color models and techniques to alter color. If you are not familiar with them you might be creating a lot of trouble for yourself.
A lot of retouching tutorials online will teach you to use a Hue/Saturation adjustment layer with -100 saturation to remove the color information from an image (this should eliminate color distractions when Dodging and burning). If you are following this advice, then you are working with Lightness in the HSL color model, which is very different from how our eyes perceive color…
Here is a quick example why it is a bad idea:
