The two principal techniques of printing are relief engraving or Lithography, and etching or "copper-plate printing".

The nobility of carved wood

The origins of printing and reproductions go back to the end of 14th century with the relief engraving on wood. At that time, European artists engraved porous boards to make and publish religious images or to make playing cards! This technique consists of hollowing out the parts of the piece of board - which was normally nut, pear, apple or wild cherry tree - the parts hollowed out would remain white - these were dug out with gouges or penknives. The image left in relief on the wood board was printed. Ink was applied to the board with a roller. The artist would then place a piece of paper on top of the inked board, and roll over it with a clean dry roller to pick up the colour from the raised sections. This process upped the stakes of engraving. Albrecht Durer was a true master of this technique between 15th and 16th century. One thinks in particular of the "Der Apocalypse", one of the jewels of German art that Dürer created between 1497 and 1498. This series of engravings on wood was inspired by Saint John the evangelist and gave rise to the first book designed and published by an artist.

Etching or Copper Plate Printing

The appearance of Engraving

The 15th century marked the advent of a new technique of engraving. Indeed, engraving in metal, in particular on copper and zinc, became a very fashionable artistic expression, which supplanted engraving on wood. This time the engraving was carried out with a dry point or engraver scratched into the metal. Ink applied to the metal board was retained in the scratches, so that the paper penetrates the scratches and absorbs the ink under the effect of the pressure - so the inverse of the method above.
The pioneer of the print in hollow with the dry point and the graver was the painter and Alsatian engraver Martin Schongauer at the end of 15th century. He put forward the subtlety of this technique and its engravings and it flourished in Europe. The blossoming of copperplate engraving in Italy was initiated by the goldsmith Tuscan, then by Florentine engravers working with Botticelli.
Albrecht Duerer's work is there still as a marvellous expression of this technique. In addition to his very famous creations on wood, Duerer, while following the way traced by Martin Schongauer, carried engraving on copper to the pinnacle. He explored all the facets of this technique and carried out a myriad of engravings whose range was universal. Duerer, in doing so, became incontestably the largest engraver of his time.

Etching, the start of a decline in Engraving

The technique of etching appeared at the beginning of the 16th century. This "indirect" process consists in obtaining engraving on metal either by scraping directly with the help of a tool and then plunging the plate into an acid bath to get a selective bite, or a metal plate is covered with a varnish intended to protect it from the acid, in which the artist makes his design with a point or needle. The acid will attack the parts of the metal that are exposed when the plate is 'etched' in the acid bath. The duration of immersion determines the depth of the grooves and hence the intensity of the features on the paper. The engraver then rinses the plate of metal with clear water, cleans off the varnish, and carries out the inking and printing in the usual way. The first etched piece was the work of Urs Graf of Switzerland in 1513.
During the 17th century, Rembrandt too let his genius express itself not only in the famous pictorial field but also in that of engraving and etching. Rembrandt devoted a lot of time to his engraving work, making one of him the greatest engravers of the 18th century. Many famous painters have tried etching themselves since then - Pieter Bruegel, Lorraine, Whistler, Manet, Pissaro, and Degas to name a few, and more recently, Mirò, Matisse, Picasso, Hopper and Marc Chagall, an etcher and very prolific lithographer since 1920.

Numerous uses

'Stroke engraving', with a dry point or needle, and etching are certainly the most commonly known techniques of copperplate engraving, but many other alternatives were developed during centuries. One thinks in particular of 'aquatint', derived from engraving with etching, and which consists in covering the plate with a layer of resin and then to heat the resin powder to fix it to the metal. This protects it at the time of immersion in acid. The difference with etching lies in that features are not traced out in the resin to be etched by the acid, but rather a 'design layer' of porous protection is added, which under the action of the acid, will produce a grain effect: only the metal exposed between the resin grains is etched away.
Surfaces having to remain white during printing are marked out with a hard varnish applied by brush before plunging the plate into the acid. This technique appeared in the 18th century and was used among others by Francisco Goya aiming at obtaining ranges of varied colours and effects comparable with watercolour washes. Other than aquatint, there is the technique of mezzotint. Here the artist uses a series of tools to dull the metal plate in varying ways - some dulling is just scratches with a point others with a burnishing wheel or coarse sand paper - this makes some areas retain more ink than others. This effect makes it possible to carry out subtle black ranges from really dark through grey onto white.

Tools

Copperplate engraving artists use similar tools to those doing linocuts or woodcuts. The main tool is a needle or tool with a steel point in the form of square or rhombus; one of the faces is a bevel cut at 45° and is very sharp. This tool allows the engraver to remove a copper chip called a burr, which will be removed before etching or printing. As this burr comes out it leaves an indent and this is where the ink will sit. The invention of the engraver was believed to be Florentin Maso Finiguerra in the 15th century. Albrecht Duerer was one of the most famous copper plate engravers. The dry point tool is similar but is very much sharper and raises a larger burr. Rembrandt was a master of the dry point.