Find Lost Details Hidden in Shadows and Darker Parts of an Image
When you have an image that has details lost in the shadows or darker areas of the image, the Fill Light slider in Lightroom 3 or the Shadows slider in Lightroom 4 can be used to recover this detail.
Don’t use either of these as a tool for lightening an image or to lighten shadows if there is nothing interesting in the shadows. Use them instead when you want to get some interesting detail out of the shadows.
The result of using the Fill Light and sometimes using the Shadow tool is that some contrast in the image will be lost – so you nay need to increase Contrast as a result of using the Fill Light slider in Lightroom 3 or apply a tone curve adjustment in Lightroom 4.