Step 8- Reduce the Saturation
Press Ctrl + U. Or go to Image -> Adjustments -> Hue/ Saturation. In the option Saturation reduce at -50.
Step 9- Multiply
Duplicate once again the model’s layer, but the one you desaturate earlier(Ctrl+J). And change the mode to Multiply.
Step 10- Blending the layers.
Now you need to blend this three layer together. With the right click underneath the layer choose the option “Merge Down.” Do this also with the multiply layer. At the end you will have just one layer.
Step 11- Using eraser at the edges.
Pass the eraser tool in the model’s outline, to get a softer look at the edges.
Step 12- Skull
Open the skull layer and put over the model’s face.
Step 13- Reduce the size of the skull
Press Ctrl+T and reduce the skull size ultil it fits with the model.You can reduce the opaticy to see through the skull layer.
Step 14- erase the parts you don’t need
Leave just the “eye” of the skull, erase the rest with the eraser tool.