Rembrandt and Pablo Picasso both used intaglio, a printing technique that involves applying ink to a metal plate that has an image cut into its surface. With this method, artists apply ink to the recessed areas of the plate rather than the top surface. The plate is then pressed onto dampened paper, which enables the paper to pick up the ink from the recessed areas. Intaglio prints often have a plate mark, which is caused by the edges of the plate pressing into the paper. In addition, the ink dries in a thick layer above the surface of the paper, giving it a textured feel.
With engraving, artists cut the image into the metal plate by hand using a sharp tool called a burin or graver. The artist can vary the depth and thickness of the lines of the cut image. This affects the final print on the paper. To create curved lines, the artist holds the engraving tool in place and rotates the plate. After ink is applied to the recesses, the surface is wiped clean before the plate is pressed against the paper.
In this method, artists use a corrosive liquid such as an acid -- called a mordant -- to cut into the metal plate. To control the action of the acid, the plate is covered with an acid-resistant substance -- called a ground. The artist creates the image by drawing lines on the ground and exposing the metal. The plate is then immersed in the mordant which cuts into the exposed metal. By leaving the plate in longer, the artist can increase the strength of the lines.
Artists use aquatint, another etching process, to create areas of tonal shading instead of lines. Rather than covering the plate completely with ground, the artist sprinkles grains of resin on the surface. When the plate is immersed in the acid, the acid cuts into the spaces between the resin. The ink is applied to the lines and crevices created by the action of the acid. The final print looks similar to a watercolor wash.
With mezzotint, artists roughen the entire surface of the plate using a tool called a rocker. If ink were applied at this stage, the print would be solid black because the entire surface of the plate would hold the ink. Instead, the artist uses a scraper to smooth out areas of the plate. When inked, these areas will appear lighter because less ink will be held there. Mezzotint creates tonal areas that look very soft.
Now living in Portland, Ore., Shawn Radcliffe has written about science and health since 1998, including online and print content for Drexel University and Oregon Health & Science University. He holds bachelor's degrees in music, English and biology from the University of Pittsburgh, as well as a Master of Science in science education from Drexel University.