lauren {elycerose}’s of flickr made this lovely image - the how to is below.
1) create a new layer and fill with dark turquoise (i used #274252)
2) set the layer to “color”
3) take the opacity down (mine’s at about 80%)
4) add a layer mask and paint back people (i lowered the opacity of the brush to about 45%) using a small, soft brush
5) add a vignette: to do this i create a new layer and then use the elliptical marquee tool, with the feather set at 200 and drag out a circle around the center of the picture (in this case anne). select the inverse and fill with black. set layer to “softlight” and then take the opacity down.