This apparently is the closet that Peter will give to a tut so i thought it wise to post here so that we all know where it is There are some great versions of his sketch scattered around the photo art site, there are some
[URL="http://www.retouchpro.com/forums/turning-portraits-into-digital-sketches-oils-watercolors/26667-how-get-rid-circles-sketch.html"]here[/URL], [URL="http://www.retouchpro.com/forums/photo-based-art/26302-tram.html"]here [/URL] and [URL="http://www.retouchpro.com/forums/photo-based-art/26252-stone-church.html"]here[/URL]

anyway this is his workflow in his own words

[CENTER][COLOR="Blue"]Here is what I have done (very quickly so not perfect)

1 dupe
2 Shadow highlight
3 Palms sketch action (faded 50%) set blend mode to multiply
4 Added Channel mixer AL set to mono (adjusted channels to taste)
5 New blank layer filled with white added mask
6 Using a brush of my own making set to 50-60% opacity painted on the mask with black.
7 New blank layer set to overlay mode, painted with black to darken areas and white to lighten. (Same as dodge & Burn)
8 Added a paper texture layer
9 Added a gradient map AL
10 Use USM to sharpen brush strokes on the masked layer.

This is the nearest you'll get to a tut for the methods I've used for this.
Using different brushes on the mask will give very different results, as will different settings to the channel mixer AL.

Peter[/COLOR][/CENTER]

Thank you Peter for your workflow and allowing me to post this here

the action Peter mentioned is also in this blog

Palms