The Color Correction node is used for adjusting the attributes such as brightness, hue, saturation, gamma, and contrast of image maps.
how to use
Open the Node editor and prepare the setup as you see in the picture below. In this setup, an image texture used and connected to the "Color Correction" node.Then, "Color Correction" node connected to the main material's diffuse channel after change it's hue and saturation values. It's pretty simple and you will use this node for many situations.