A technical dictionary of printmaking, André Béguin.

An engraving process which is part of the intaglio technique of engraving. Whereas engraving with a graver or burin cuts metal out of the plate and etching removes metal by dissolving it, the dry point technique only displaces the metal on the plate. In dry point the metal surface is scratched, gouged, punctured, and scraped but the metal is not removed, it is just pushed to the side, forming a kind of curl.
Thus the lines will present a metal burr which, when looked at through a magnifying glass, shows up as a kind of broken metallic wave. This burr must be kept intact on the plate since it is this element which characterises the technique when it is printed. In fact, dry point owes its particular results to the ink being caught both inside the lines as well as in the burr around the lines.
Dry point is done on naked copper plates (no grounds are used) or, at times, on zinc plates. Zinc plates are easy to work but unless they are steelfaced they are not resistant enough to print. Plastic plates are sometimes also used partially because the design made on them can be checked by looking at the plate against sunlight. The drawback in using plastic is that the softness of this material does not allow for more than about ten impressions. If one so wishes it is possible to prepare a design either by tracing it or by drawing it directly onto the plate, but this must be done before engraving the plate.
Dry point can also be done on a copper plate that has a ground on it in which case the dry point will be mixed with an etching technique. The finer lines engraved on the ground will be quite superficial whereas the strong blacks (after printing) will be deeply engraved. The mordant ends up etching the lines to more or less the same depth. In fact the lines must be relatively deep because the triangular cross section of the lines do not hold much ink. On the other hand the cross hatched sections of the plate (due to the burr and crossed lines) will print very intense and velvety blacks.
The tool with which one works is also called a dry point. It has a very fine cutting point which is either sharpened like a needle or may have several facets. The dry point is used like a pencil (and not like a graver which is pushed along). Points of varying size may be used according to the desired results.
Diamond-tipped points may be used to draw very fine and precise lines. Work on the plate must be done with one's hand raised or resting on a hand rest* because there is always the danger of disturbing the finer burr. Some artists have found that working on an easel was the best solution to the problem. In order to avoid the oxydation that plates might undergo while being worked on it is best to oil them.
Dry point engraving must retain its spontaneous and sketch-like characteristics. It is a technique especially suited for artists.
The printing of dry points is a very delicate task because the burr (which is very fragile) must not be damaged. Furthermore, the inking must reflect the intentions of the artist and this too is a difficult task. In fact the ink often clings to the plate in different ways depending on the direction in which the plate is wiped. What's more, the pressure of the press roller makes the ink around the burr spread out and spot.
In order to protect the burr one must have the plate steelfaced as without such protection the burr will resist for only a very few impressions. For much the same reason it is not a good idea to print states* while drawing on the plate.
The impression of a dry point is called an etching. The most sought-after impressions are the ones that still show the effects of the burr. Such impressions are often termed "full of burr". Since the burr is worn off easily the numbering of dry point impressions is considered to be very important.
Although various attempts were made to etch dry points before the time of Dürer it may be said that he was the first one to use this technique. In 1512 he etched "St.Jerome in the Wilderness", "The Man of Sorrows", and a "Holy Family" in which the grays have half-tones that are completely different from those achieved in his engravings. Rembrandt, who used every technique available, also used dry point etching which in his hands gave a tragic turn to the subject as is the case in the last states of his "Three Crosses" (1655). Lebas (1707-1785) also etched with a dry point but it was not until the 19th and 20th century that this technique was adopted for its inherent qualities. Some artists engrave with a dry point (because it is held more easily than a graver) but then remove the burr so that the finished product looks more like burin or graver work.

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