Color Correction/Vibrance  

The vibrance operator cleverly increases the intensity of the more muted colors and leaves the already well-saturated colors alone. It's sort of like fill light, but for colors. Vibrance also prevents skin tones from becoming overly saturated and unnatural.

Composer supports adjusting the Master Vibrance (RGB channels) or per channel.

Vibrance can either be increased or decreased.

Below is an example where the red in the image has an increased vibrance.

Vibrance is often used to give the image “additional punch”.