Peter,This technique isolates texture and colour on two separate layers so that you can clone out the colour and leave the texture (detail) untouched. I use Tony Kuyper's V6 panel which has this built in as a 1-click action. However, as seen in the linked video, it is not hard to do it manually -https://www.youtube.com/watch?annotation_id=annotation_3026130903&feature=iv&src_vid=y9niGvZClh8&v=zQNkKiLDD88