sophisticated form, it survived in advertisements and trade catalogues until about 1930. With this change, wood engraving was left free to develop as a creative form in its own right, a movement prefigured in the late 1800s by such artists as Joseph Crawhall II and the Beggarstaff Brothers. Timothy Cole was a traditional wood engraver, executing copies from museum paintings on commission from magazines such as The Century Magazine. Technique Wood engraving blocks are typically made of boxwood or other hardwoods such as lemonwood or cherry. They are expensive to purchase because end-grain wood must be a section through the trunk or large bough of a tree. Some modern wood engravers use substitutes made of PVC or resin, mounted on MDF, which produce similarly detailed results of a slightly different character. The block is manipulated on a "sandbag" (a sand-filled circular leather cushion). This helps the engraver produce curved or undulating lines with minimal manipulation of the cutting tool. Wood engravers use a range of specialized tools. The lozenge graver is similar to the burin used by copper engravers of Bewick's day, and comes in different sizes. Various sizes of V-shaped graver are used for hatching. Other, more flexible, tools include the spitsticker, for fine undulating lines; the round scorper for curved textures; and the flat scorper for clearing larger areas. Wood engraving is generally a black-and-white technique. However, a handful of wood engravers also work in colour, using three or four blocks of primary colours—in a way parallel to the four-colour process in modern printing. To do this, the printmaker must register the blocks (make sure they print in exactly the same place on the page). Recently, engravers have begun to use lasers to engrave wood. It is possible to print in colour using several woods: one for each colour in addition to the default colour of the paper: Notable wood engravers Joseph Alexander Adams Leonard Baskin Elisa Berroeta Thomas Bewick Torsten Billman James Bostock (painter) Edward Calvert Vija Celmins Asa Cheffetz Timothy Cole Arthur Comfort Rosemary Feit Covey Honoré Daumier Victor Delhez John DePol Stevan Dohanos Gustave Doré Nicolas Eekman Fritz Eichenberg Andy English M. C. Escher William Biscombe Gardner Tirzah Garwood Eric Gill Barbara Greg Gertrude Hermes Greta Hopkinson Barbara Howard Blair Hughes-Stanton Eduard Magnus Jakobson David Jones (poet) Rockwell Kent Paul Landacre Clare Leighton Frank Leslie William James Linton Iain Macnab Barry Moser Zdeněk Mézl John