Can you elaborate a little Rod?
By using the curves tool on a selection you can change the color to lighter or darker shade.
This is very, very, handy when trying to give an added or healed area of an image the same color shading.
For instance if i select a wire area in the image i want to remove or cover up.
I can then move that selection to another part of the image i like and copy>paste the selection.Now just make that copy and paste a new layer.Move the copied area over the area you want to fix and then use colors curves to fix the shading. If it's needed.Which it usually is. I have fixed many panoramas this way and older photographs.It's almost impossible to see the seams.