Tabrizi, just a quick try on your wonderful portrait. One approach could be to create another layer on top of the image, completely black. Then you cut out a shape of the main part, maybe oval. Also helpful if the shapoe is feathered and not a hard cut. Then two more steps: One is to soften the mask you have created with Gaussian blur. Finally adjusting the effect by manipulating the stenght of the layer. Let me know if this is not clear!

Origibal is here: http://www.pbase.com/stfchallenge/image/107259269