To see the Curves dialog box, go to IMAGE...Adjustments...Curves (or Ctrl+M)
The box on the right is basically a simple 'graph' with a diagonal axis. To adjust the Curves in your image, you will click on this axis and drag this line. As you drag your axis to the bottom-right, darkness will be added to your image.
Drgging towards the top-left adds lightness.
You can add multiple 'control points' to your axis and, as well as physically dragging, once you have clicked to add a point, you can use your keyboard arrow keys for more precise adjustment. |