
Photo: From "digital Photography" By Jay Dickman And Jay Kinghorn With Permission
From Mcgraw Hill

Step 6
I want to increase the saturation of the greens in the image, but want to make sure that I don't oversaturate colors beyond what the printer can print, so I turn on the Gamut Warning feature, which places a gray overlay on out-of-gamut colors. Next, I create a new Hue/Saturation Adjustment layer and add 10 points of saturation (right). This makes the grass more vibrant (bottom)