To my knowledge, wood engravings are relief prints (raised area
prints--check out http://freespace.virgin.net/a.english/how.htm). They are
very fine lines--cut on the dense end grain of wood. Due to the fine
detail--additions are limited (fewer impressions off the plate).
Copper/metal plate engravings are intaglio (the ink in the grooves
prints--and etching press is needed). I did an IxQuick search
(http://www.ixquick.com ) and could not find a quick answer to the posted
question.