Go to www.nikonusa.com, software downloads and download the free trial of the new Nikon Capture NX.
It has a feature where one can place a selection dot on a color and have sliders offer total control of that color in the image. I know there is a lot more, but haven't had time to investigate.
I just played for a few minutes but the magazines say this is as powerful a Photoshop and MUCH simpler.
Your further comments Please!