Line Etching Effect for Photographic Images
This Demonstration produces halftones from a continuous tone image, replacing rows and columns of pixels by a spiral of varying gray-level intensity or hue. This gives the image an etching effect similar to the medieval single line engraving technique . Use the locator to move the center of the spiral.
 PhotoConservation. "Single Line Engraving." (Jul 26, 2012) www.photoconservation.com/index.php?option=com_content&view=article&id=99%3 asingle-line-engraving&catid=35%3 aprintprocesses&Itemid=63.html.