Burnt- in edge effect

To add a burnt in edge effect on a photo with some degree of flexibility

1. create a new adjustment layer.. select levels

2. in the levels window, drag the markers to the left so your entire photo is black

3. use marquee tool to select the area you want

4. feather it ( shift F6)

5. choose the layer mask and fill with black ( this reveals the photo)

6. again, use the levels markers to adjust the appearance of the edge. I adjusted the output levels to get the grey affect in this photo