Here is an example of using layers in photoshop. Two consecutive frames were taken; in one measuring the exposure on the water, and in the other one measuring the light on the sky. Combining these two frames game me a pefect exposure of the entire frame. Mid tones and and highlights were silghtly touched, but color temperature was not modified, I must clarify. It was a beautiful Fall afternoon in Tribble Mill Park, Lawrenceville, GA.