Made sketch using "dodge mode" to inverted desaturate. Then sharpened a green channel copy extensively. Added an empty levels layer and used apply image to place the sharpened green channel in as a layer mask on this adjustment layer. I think I set the mode to luminosity or multiply and used the opacity slider to set. This was to sharpen the detail withing the pattern filled sketch of the rocks, but not sharpen artifacts. Must remember this sketch and sharpen method for peoples faces....