Engraving and Etching
Engraving and Etching
Engraving and etching are processes used to make intaglio prints. An intaglio print is made from a plate, usually a metal one, which has been had lines drawn into its surface. These lines trap ink that is rolled across the plate’s surface. When the surface of the plate is wiped with a cloth, the lines retain their ink. A piece of damp paper is placed on the plate, and the two are run through a press, which forces them together. This process transfers the ink from the plate to the paper. In an etching, acids are used to draw into the plate. In an engraving, sharp tools are used to draw directly into the metal.
Engraving and etching have been used in printing for hundreds of years. Before the invention of modern, photographic-based techniques, they were the most commonly used method for reproducing images. Newspapers and printed advertisements formerly used engravings. Stamps and paper money are still printed using the engraving process because of its ability to reproduce fine lines and sharp details.
Engraving first became popular in Europe during the fifteenth century, when paper became available far more widely than it had been previously. From the beginning, intaglio printing was used for both the sacred and the profane. Artists made engravings of religious scenes, while craftsmen used the new technique to make copies of famous paintings or decks of playing cards. In an age when the printing press and movable type were first being invented, these were the equivalent of today’s mass-produced posters.
Propelled by the genius of artists like Albrecht Dürer (1471-1528), intaglio techniques grew quickly. Artists learned to create various kinds of shading through the use of dots, called stippling, and groups of parallel lines at various angles to each other, called cross-hatching. Engraving requires drawing a line while pressing into a plate the correct distance to create the desired shade and line width. Some artists rejected the tool used for this, called a burin, which has a square or diamond-shaped tip and shaft and creates very clean lines. They preferred the softer look created by cutting the plate with a needle, a technique called drypoint. A needle causes ridges of metal to rise next to the groove it cut. These ridges catch large amounts of printing ink, which produce rich, soft blacks when transferred to paper. Unfortunately, the ridges wear down rapidly, making drypoint unsuitable to large press runs. In
engraving, any ridges caused by cutting the plate are removed with a sharp instrument called a scraper.
Etching became popular during the sixteenth century. It evolved from fifteenth-century techniques for putting patterns on swords. Armorers would cover new swords with wax, then scratch through the wax, and put the sword in a weak acid until the acid bit a line in the metal. To make an etching, a metal plate is first covered with a ground, a thin layer of acid-resistant material. The artist then scratches gently into the ground with an etching needle, exposing parts of the plate. This process is much more like drawing with a pencil than engraving is, and many artists preferred it. After the ground is drawn on with the etching needle, the plate is put into acid, which eats at the plate where the needle has exposed it. The length of exposure to the acid determines the depth of the line.
The same principals are employed today, though techniques have been refined and expanded. Etching grounds have evolved from an unpredictable waxy substance to harder varnishes used by instrument makers, to petroleum derivatives like asphaltum. Early acids used on copper were made from a mixture of sulfuric acid, sodium nitrate, and alum, but they produced virulent fumes. Etchers switched to a weaker but safer mixture made from vinegar, salt, ammonium chloride, and copper sulfate. This solution produced rich detail, and was used by Rembrandt.
Nitric acid was often used beginning in the late eighteenth century, but because of its strength, it sometimes destroyed fine details. Around 1850 a popular mixture was discovered consisting of hydrochloric acid, potassium chloride, and water. Sometimes called Dutch
Drypoint— Technique in which a plate is drawn on directly with an etching needle.
Engraving— Printmaking technique in which a metal plate is drawn on directly with sharp, hard instruments.
Etching— Printmaking technique in which lines are created in a metal plate through the action of acids and acid-resistant grounds.
Ground— An acid-resistant substance painted onto etching plates.
Steel facing— Adding a thin layer of iron through electrodeposition to strengthen plates made of weaker metals.
mordant, it is still used today, and is the most widely used copper-etching agent, along with ferric chloride.
Plate usage has also evolved. The first etchings were done on iron plates, which corroded quickly. Around 1520, the Dutch artist Lucas van Leyden (1494-1533) began using copper plates, and other print-makers swiftly followed. However, while copper plates can hold a lot of detail and are not expensive, copper is too soft for large editions. In van Leyden’s day, people used to pound it with hammers, creating a random alignment of the copper molecules, and thus a stronger plate. Today, copper can be bought in an already hardened form. Better still, after etching or engraving, copper plates can be strengthened by putting a microscopically thin layer of iron on them through electro-deposition. This process is called steel facing.
In electrodeposition, copper and iron plates are placed in an electricity-carrying solution. Direct-current electricity is run through the plates, giving the copper a negative charge, and the iron a positive charge. The current removes iron ions, carries them through the solution, and deposits them on the copper plate. This technique, invented in France in the mid-nineteenth century, quickly spread throughout the world.
Zinc is often used as an etching plate because it is less expensive than copper. It is softer than copper, however, and requires a two-stage process for steel facing that results in some loss of detail. Zinc’s softness can be an advantage in etching, where the plate is sometimes changed by scraping and polishing. It is too soft for fine-line engraving, however.
Brass, an alloy of copper and zinc that is harder than either of them, is sometimes used for plates, and costs about as much as copper. Steel is the material of choice for engraving plates. Because it is so hard, very large editions can be printed. Steel also yields extremely fine detail. One disadvantage of steel is that it rusts easily. It must be stored carefully and protected from moisture with a coating of etching ground or oil.
Ayres, Julia. Printmaking Techniques. New York: Watson-Guptill, 1993.
Artelino GmbH. “Intaglio Printmaking” <http://www.artelino.com/articles/intaglio_printmaking.asp>(accessed November 24, 2006).
Metropolitan Museum of Art. “The Print: A Renaissance Invention—Intaglio” <http://www.metmuseum.org/toah/hd/intg/hd_intg.htm> (accessed November 24, 2006).
Scott M. Lewis