Etching and engraving are both methods of cutting lines into a hard surface, such as metal. The primary difference between them is that engraving is a physical process and etching is a chemical process. An engraver uses sharp tools to cut lines directly into a surface, while an etcher burns lines into a surface with acid.
Hand engraving, which is a method of decorating metal with text and images, is an ancient art. For centuries, hand engravers have used sharp metal tools to draw directly onto jewelry, guns, silverware and other items; the inscriptions frequently seen on the inside of wedding rings are a familiar example. Print engraving dates back to the mid-1400s, and was the dominant method of artistic printing until it was superseded by etching in the early 17th century. It takes considerable strength and skill to cut furrows into metal plates; because etching requires much less effort, many artists switched to that medium when it became widely available. However, print engraving remained a common commercial method of reproducing artwork until the advent of photography.
In the simplest form of etching, the artist covers a copper or steel plate with a layer of wax and then scratches a design through the wax with etching tools. When the design is finished, the artist dips the plate into an acid bath, which eats away any exposed metal. The same basic principle applies to other forms of etching. In glass etching, for example, artists put acid-resistant designs on glass and then apply a hydrofluoric acid solution. The acid attacks the unprotected glass, leaving it with a frosted appearance that reveals the etched design. Hobbyists use a very similar process to create electronic circuit boards.
Use in Printing
Etching and engraving are both forms of intaglio printing, which is defined by the cutting of lines into a flat surface. Although the method of producing these lines is different, the printing process is identical. The plate is inked and wiped clean, leaving ink only in the etched or engraved lines. The plate is then pressed against a sheet of paper to transfer the inked image. The deeper the line, the more ink it holds and the darker it prints. Etchings and engravings both print in reverse, so the artist must draw the image in reverse when working with these media.
Because engraving creates a very hard, thin line, engraved prints tend to have crisp edges and sharp details that most other printing methods can’t achieve. For this reason, engraving is an ideal method for printing currency. Etching, by contrast, tends to produce a fuzzier line; this happens because the acid burns laterally under the wax, created a wider and rougher line than the artist originally drew. Also, because the artist doesn’t have to exert as much force on an etching plate, etchings tend to have a softer, more fluid line closer to that of freehand drawing. Fine artists -- historical and modern -- often combine etching and engraving in a single artwork, which produces a wider range of visual effects.