From PiXimperfect:
Control the Light with the Amazing "Horizontal Curve" Technique in Photoshop! Discover the most natural way to adjust the brightness of any area without disturbing the colors, using a simple straight Curve.
In this tutorial, we will use a Hue/Saturation adjustment layer and combine with a Curves adjustment layer to create a "Light Map" that would allow us to control the amount of light all throughout the image.
B&H carries Adobe Photography Plan subscriptions.