Pity this link isnt working anymore as it is one of my favorites
but this is the gist of it
dup original >desaturate >duplicate
invert top layer
change top layer to colour dodge
gaussian blur ( so can see soft detail)
diffuse ( aniso )
new layer
use history brush to bring back some soft colour using a chalk brush ( or similar )
change blend mode to hard light
works nicely on furry animals ( not tried on buildings etc )
this was done quickly just to give a rough idea
photograph from
www.geekphilosopher.com
Palms