Engraving is considered the oldest form of intaglio printing. A plate is incised with a burin, a steel rod with a sharp beveled point. The incised V-shaped lines hold the ink after the plate is wiped. Stipple engraving uses a burin to make dashes rather than lines to produce a lighter tone. Stipple engraving is often used with regular engraving. Drypoint is an intaglio process, like engraving, that uses a sharp steel point to scratch directly into a copper, zinc or steel plate. The burr or raised portion, that is thrown up on either side of the lines catches and holds extra ink. This extra ink produces a rich tone in the print. The burr is fragile and usually produces only twenty to thirty good impressions. Wood Engraving is a relief process. They are made from end-grain wood (the end cut of a board, across the grain). Boxwood or other hard woods are used for their fine grain. Usually small squares of wood are joined together to form the block. A burin, that forms a V-shaped line, is used for carving. Line-block or photoengraving is a photomechanical process that reproduces a line drawing. These are done with electronic scanners and automatic etching machines. Line-block copies of woodcuts and wood engravings can be difficult to identify. The lines in the reproductions do not show the variations of tone seen in the originals.