Thomas Bewick drew directly onto a woodblock or rubbed a transfer drawing onto it. He would then hold the block on a leather-covered casting (or sandbag) which allowed the block to be manoeuvered by one hand while cutting with a tool (graver) held in the other hand. The tools had different cutting edges for the type of cut required to show different textures and tones. Bewick generally made his own tools. The part of the design which would be white in the finished picture was cut away. It was then 'relief' printed. The block was inked with a roller, then a piece of damp paper placed on top of the block. The two were put into the printing press, and the pressure transferred the inked design onto the paper. The process produced a mirror image of the original design.
Two reasons make Bewick's engravings special. First, he always cut into the cross-grain of boxwood, a very close-grained hard wood. (Boxwood was slow-growing expensive which accounts for the small size of Bewick's blocks). This hardness meant he could cut more detail than in the older technique of woodcutting whereby a softer wood was cut along (not against) grain. Secondly, he devised a method of lowering the block during printing that allowed him to control how much ink touched the block. This meant he could show light and dark (tones) areas in his engraving. Grey areas, rather than stark black or white, are characteristic of his engravings.
Often Bewick's engravings are in the form of a vignette or tail-piece rather than a large full-page engraving (called a "figure") of an animal or bird. Tail-pieces were usually placed at the beginning or end of a page or chapter. Their purpose was to fill a blank space, maintain the reader's interest or simply to use up remnants of expensive boxwood. Bewick called them "tale-pieces". He explains in the introduction to 'Land Birds', "I interspersed the more serious studies with tale-pieces of gaiety and humour; but yet even in these seldom without an endeavour to illustrate some truth, or some moral point." Often these scenes were set in pretty frames, usually oval in shape.