To see the effect of using curves, try this...If you have an area of shadow in your image that you wish to bring out some detail, click on that part of the image...the corresponding clicked point will show up as a point on the straight line (curve). Now move the straight line at the point where it was indicated...move it until you get the desired detail in the shadow area. You now have a curve! Now go to the highlight part of your image, click again...notice the point on the curve, adjust this point to bring back any blown out areas (if necessary). Play around....oh, one other thing...the move does not need to be dramatic...start with subtle moves first. Also, you can add more points, adjust midpoint etc.... Have fun!

In youth, we learn....with age, we understand.