days of mezzotint an angle instrument was introduced which regulated with exactitude the series of progressive angles.
The method of procedure is as follows: The plate has a series of chalk lines drawn upon it about three-quarters of an inch apart. Between these lines the cradle is worked over the plate from the top to the bottom in a series of parallel paths. This tool is a wide chisel with curved blade like a cheese-cutter and having teeth, the method of using this in rocking motion gives it the name of "rocker" or cradle. This operation of crossing the plate is termed a "way." New parallel chalk lines are drawn across the plate from one side to the other and a similar series of paths worked across the plate cutting the former grooves at right angles. This is another "way." Similarly by travelling across the plate from corner to corner, other paths are worked which cut the former lines at an angle of forty-five degrees. To make this clearer, if it were a map these latest paths would run from south-west to north-east, and from south-east to north-west. This operation is repeated in graduated angles from sixty to a hundred times, and the entire surface of the plate is reduced to a state of "burr" of infinitesimal size.
But the beginner need not bother himself over this laying of ground. The object is to produce a plate covered in every place with a burr which if inked would give an impression on paper of a rich velvety black. This is then the starting-point of mezzotint engraving.
