To start your own 'grunge' manipulation, I recommend that you select a picture that already has a dark feel about it.
One of the absolute necessities when it comes to grunge, is texture. Take your time when choosing your textures to make sure they will work well with what you are doing. Keep this in mind: the higher the quality of texture, the better the results. For my example I will be using cracks in the earth and walls etc.
Concentrating more on the face than the rest of the body, take the second texture, resize it, and then position it around the middle of the face. Using a large soft brush with the eraser tool (around 100px), get rid of the main areas of brick that are surrounding the crack, and for the more intricate areas zoom in with a magnification of about 400% and use a smaller soft brush (about 8px). Once you are satisfied, change the textures layer blending mode to Multiply.
Now import the first texture into the workspace, again resize it to your liking, and then apply the Overlay blending option.
Just like before, using the eraser tool, get rid of the unwanted texture, zooming in and using smaller brush sizes where needed. I warn you, this may be quite time consuming if you are not used to working like this before. Once completed, duplicate the layer to enhance the texture.
