LITHOGRAPHY

The term lithography comes from the Greek words for stone and writing.

The process of lithography was invented in the 1790’s by Aloys Senefelder in Munich, Germany. Senefelder, an impoverished writer, was trying to develop an inexpensive way to publish his plays. After accidentally discovering the effects of greasy ink on limestone, he patented the process and spent the rest of his life perfecting it. Today, lithography is used for the commercial printing of magazines and posters as well as fine art works.

The principle of lithography is that grease and water repel each other. In lithography, the artist draws on a stone or aluminum plate with a greasy crayon or with tusche, a liquid grease. Lithographic stones can be used over again by resurfacing or graining the stone with carborundum grit. Plates can also be made light sensitive and used with a photographic image. The drawing is processed with a slightly acidic etch, consisting of gum arabic mixed with drops of nitric or phosphoric acid. The drawing becomes hardened and the surface of the stone becomes desensitized to grease. The etching process leaves a gum Arabic mask around the drawing. The drawing is washed out with lithotine. The gum Arabic does not wash away because it is water-soluble. Ink is then rubbed into the drawing, and the gum is washed away. The stone or plate is kept moist with a wet sponge while the printer rolls up with an inky roller. The ink, being greasy, attaches itself to the drawing and not the clear areas, which are wet and repel the grease.

When the stone or plate is rolled up with ink, the printer lays a sheet of paper over the stone. A thin sheet of plastic called a tympan goes on top. A bar coated with leather or Teflon is pulled down onto the tympan with enormous pressure. When the printer turns a crank, the bed of the press moves, the bar slides over the tympan, and the image gets transferred to the paper.

Artists were attracted to lithography for it’s resemblance to charcoal drawing. Honoré Daumier, Henri de Toulouse Lautrec, Winslow Homer, Pablo Picasso and Jasper Johns are among the many artists who have made lithographs.