What Curves does is it allows you to adjust the amount of color and the luminosity (brightness) of each color shade within your image (red, blue, and green). This feature gives you a high degree of control in many aspects of your image. Because you can add ranges of adjustments based on intensity, you can use Curves to fine tune your image in ways that other adjustments can't.
The Curves interface is an interactive grid that allows you to control aspects of an image with a simple line.
Horizontal values are the intensity input or the information going into the image and the vertical values are the intensity output or the information coming out of the image.
If you reshape the left half of the curve, it will affect the darker half of an image, and reshaping the right half will affect the brighter half. The diagonal line represents the image in its neutral position. If you move that line above the diagonal guideline, it will cause the affected areas...
