A technical dictionary of printmaking, André Béguin.

. An ancient technique for engraving on metal plates. The lines of the plate were engraved in much the same way as a block of wood. In other words the lines were isolated and the areas removed were those meant to print white. In short it was a relief technique practiced on metal.
In order to avoid the excessive contrasts between the blacks and whites, of such plates engravers were wont to introduce rough half tones by introducing little holes which printed white. By varying the distance between the holes some half tones could he brought about. The holes were made with a sharp punch that was driven into the plate by hitting it with a hammer. The punch produced a little craler whose edges exibited a little curl called the burr which was removed with a burnisher. If one considers the dotted manner from the point of view of the values it produces it can be considered to be the ancestor of white line engraving*, of the negative shading medium*, and of the negative screen, since each one of these accentuates white designs on a black background as opposed to line drawing, which works with black designs on white backgrounds [* white , graining].
If one considers the inking method then it can be said that dotted work is the opposite of punch engraving whose goal it is to create values by making a multitude of little holes with a graver.
As of the 11th century the monk Theophilus has described the work of goldsmiths and had subdivided their work into two separate categories: opus* punctile and opus interassile. The former of these techniques was adopted by engravers to work on their plates and came to be known as the dotted manner. Actually the two techniques were more or less combined since the interassile was used to do line work with a graver (or burin) while the punctile or dotted manner was used to bring about the half tones. Later on, in the 18th century, these techniques were used again (having been developed somewhat) in white line wood cutting.
Speaking more generally and from a technical point of view one may say that dotted work is much like punch and hammer work in that the tool used is hammered rather than being pushed along like a graver.
It is a much discussed point whether dotted work preceeded wood cutting but it would seem that, in printmaking, wood cutting came first. Dotted work appeared only towards the middle of the 15th century. The technique of dotted work hardly foreshadowed great future use and was, despite its preciousness and charm, soon bypassed by line engraving (intaglio inked) whose immense advantage was to be able to ensure the depth of planes. In fact, dotted work is such that it is most difficult to render more than the first plane (ever increasing work was being done on perspective in the course of the 15th and 16th centuries) and hence it died out by the end of the 15th century.

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