A clever method to get realistic colors in important areas of an image; such as skin, grass, hair, and sky is to open a color image containing true colors such as black or white.
You can then use the Color Picker to move the mouse pointer to a true color, take a sample from the true colors and return to your …

When the Color Picker window is open click on the button Custom. The default is Rantone Solid Coated. However, Photoshop offers several color combinations. To select a different color pallet, click and hold the mouse over the Book pop-up menu and you will see a list of color combinations to choose what you want.