Lithography | Research & Encyclopedia Articles

Lithography

Lithography, which has developed into one of the world's most popular processes for mass-producing images, was invented not by an engineer or a trained printer, but by a writer. The process, however, has its origin in a humble laundry list. Its inventor, Aloys Senefelder (1771-1834), was a struggling German playwright whose family had little money. Unable to afford the cost of printing his plays, he began to experiment with ways of engraving the manuscripts himself. Senefelder met with little success until one day in 1796, when, asked to take down a laundry list by his mother, he wrote the list in grease pencil on a polished limestone slab with which he had been experimenting. It occurred to him that he could use the water-repellent qualities of the grease coating to produce an acid etching on the slab. Over two years, he ultimately arrived at a different approach based on the same concept. In Senefelder's process of lithography (literally, "writing on stone"), the design to be reproduced is drawn directly onto a stone slab or plate. The slab is then dampened completely; the water, however, is repelled from the grease-covered areas. When a coating of ink is then applied to the plate, it washes away from the wet areas, but adheres to the grease marks.

Senefelder found that the image created by pressing this plate to paper was exceptionally faithful in reproducing even fine lines in the original; he also found, later, that a solution of gum arabic and nitric acid was even more effective than water in completely repelling ink from the non- greased areas. Also, the stone ultimately was replaced with metal plates. Lithography was quickly embraced by printers as a quick and effective method of mass-producing commercial illustrations and sheet music, and after Senefelder published A Complete Course of Lithography in 1818, it developed into a popular means of creating original art, used by painters Eugène Delacroix, Théodore Géricault, and Goya. In the mid-nineteenth century, a process was developed for using a series of different plates to produce multi-colored lithographs. The mass-market art produced by Currier and Ives, an American firm, was made possible by this technique, as were the now-famous posters of French artist Henri de Toulouse-Lautrec. Along with the general automation of printing processes that occurred in the nineteenth century and though the turn of the twentieth century, the application of photography to create images on plates, through a process called photolithography, shaped modern lithography. In photolithography, the printer shines bright light through a photo negative onto a thin plate coated with light-sensitive chemicals. The areas of the plate struck by the light harden into a reproduced image, serving the same function as the grease design in early lithography. Most lithographic printing today is done through a process called offset printing, in which the thin metal plate is clamped to a cylinder and inked, and then transfers the image to a turning rubber cylinder; finally, the rubber cylinder transfers the ink onto a sheet of paper as it rolls beneath it. Like other automated, cylinder-based printing techniques, offset printing is able to print sheets repeatedly on both sides at very high speeds. Because of this, and because of the fact that photolithography allows photographic reproduction of print and photos as well as art, lithography remains today one of the most widely used printing methods.