Would darkening the tones in one small area improve your photo? Luckily, Adobe Photoshop has a simple tool to help you correct this issue: the burn tool!
Click on the burn tool in the vertical toolbar on the left hand side of your workspace. The burn tool looks like a little hand, where the thumb an index finger are making a circle. The burn tool shares space with the dodge and sponge tools.
Step2
Look at the top of your control bar. You have several choices to make. First, you can adjust the "brush" of the burn tool, in terms of brush profile and size. You can do this by clicking on the button that shows your brush and the brush size.
Step3
Select whether you want to darken the shadows, highlights of midtones of your image.
Step4
Decide how much exposure you want to adjust. Start out conservatively. It's easier to add more than take away adjustments. Remember that your image onscreen is brighter than it will print out, so you might want to print out a proof before you finish.
Step5
Check your image to see the changes take effect. Remember to maintain a consistent light source in your image. Your shading should be on the opposite side of a visible light source.
Tips & Warnings
Always keep a spare file of your image before you start making adjustments.
Get in the habit of duplicating your layer before you begin.
Avoid making shadows too dark. You will lose photo detail.