Wood Engraving

The appearance and line quality of a wood engraving is similar to that of a copper-plate engraving. The lines are rigid, noticeably tapered at the ends, and vary in thickness and length to create tone and texture. Wood and copper differ insofar as a copper engraving is printed using an intaglio technique where the incised lines receive ink, and print on paper as black. Wood engravings are printed in relief; the ink is rolled onto the surface, so the incised lines remain white. 

Source: http://www.ifpda.org/content/collecting_pr...