Curves

The Curves adjustment allows you to precisely adjust the tonal range in your image. By left-clicking on the curves chart, you can add control points that can be dragged using the mouse. The x-axis of the chart represents input values, while the y-axis represents output values. Therefore, adjusting the curve in the bottom-left of the chart affects darker areas, and adjusting the curve in the upper-right affects brighter areas.

Mouse Controls Left-click this will add a control point Right-click (while hovering over a control point) this will delete the control point.

The Curves adjustment panel.

When processing in RGB color space, the individual red, green and blue channels can have independent curves. When in Lab color space, only the luminance can be adjusted.