The Selective Color adjustment provides a way to subtly adjust and enhance colors in your image on an individual channel basis. It makes a useful tool for color balance corrections.
Apply this adjustment via the Adjustment button on the Layers panel or via Layer > New Adjustment.
The following settings can be adjusted in the dialog:
Color—determines the color to be adjusted. Select from the pop-up menu.
Relative—when selected (default), color is added or subtracted in proportion to the amount of that color present in the source pixels, giving a more natural effect. If this option is off, colors are added or subtracted based on the absolute percentage specified, regardless of the how much of that color is present in the image.
The sliders control the levels of the named color in the selected Color. Drag the slider to the left to decrease the level of the named color, drag the slider to the right to increase it.