I attempted to make the skin tones of the three girls more similar
using a curves adjustment layer for each child.
First, used an Inverted Average blur copy of background image for
a little overall color correction.
Gaussian Blurred another background copy to blur the studio background.
3 curves color correction layers
PWL layer to vignette the border and highlight some dark areas
on faces and hair.


forum discussion: http://forums.dpreview.com/forums/read.asp?forum=1006&message=22787490&changemode=1

original image by Davud: