How to Fix an Underexposed Digital Photo
If your take a photo that you love but it’s underexposed, you can rescue the image in your image-editing software. Many image editors let you correct underexposed pictures, making them underexposed no more. This is how you do it in Photoshop Elements:
1Open your image editor and choose File→Open.
Navigate to your underexposed image and click OK. The image opens in your image editor.
3In the Layers palette, change the duplicated layer’s blend mode to Screen.
This blend mode brightens the image considerably.