Adam Dachis over at Lifehacker offers a simple method for correcting underexposed photo with any image editor that supports layers, inversion, and Overlay blending mode. Simply invert a duplicate of the photo, set the blending mode of the inverted layer to Overlay, and then adjust the opacity of the layer to suit your taste. While it’s certainly not a pro photography tip — other techniques including adjusting the curves and levels may be better — it’s a quick and easy trick that may be good to know.

Fix Your Photo?s Exposure Problems in Seconds With This Simple Trick [Lifehacker]