Now when I set the layer to overlay again, I get the following:

Click image for larger version. 

Name:	gradientMethod11.jpg 
Views:	207 
Size:	42.4 KB 
ID:	11988

So to recap, by using an overlay layer you can change a flat image to one with a bit of form and shape. This can be used to create light and shade fro scratch, but can also be used later on to enhance the light and shade already present in a piece. The trick really lies in creating a reasonable layer.

Here's the three different images created in three different ways during this tutorial. I hope it was useful.

Click image for larger version. 

Name:	End.jpg 
Views:	173 
Size:	42.7 KB 
ID:	11989 Click image for larger version. 

Name:	gradientMethod7Better.jpg 
Views:	165 
Size:	42.2 KB 
ID:	11990 Click image for larger version. 

Name:	gradientMethod11.jpg 
Views:	207 
Size:	42.4 KB 
ID:	11988