Lithography...
Lithography, from the Greek word 'litho' for stone, was invented by Aloys Senefelder in Bohemia in 1798. It was the first new printing process since the invention of relief printing in the fifteenth century and is still used today in many forms. Lithography is described as a planographic printing method since the image is printed from a flat surface rather then a raised surface.

The process of lithography is based on the simple principle of the repulsion of oil and water. The image is drawn on the surface of a flat stone or metal plate that has been specifically ground or polished for this purpose. The artist use's an oil-based medium to draw the image onto the print block. The range of oil-based mediums are endless. In the earlier processes, and today in fine art pieces, the stone would be etched — or set — by a chemical process using an acid emulsified with gum arabic. This process leaves a layer of salt that surrounds the image. Using lithographic turpentine, the printer then removes the greasy drawing material, leaving only the salt layer; it is this salt layer which holds the skeleton of the image's original form. When printing, the stone or plate is kept wet with water. Naturally the water is attracted to the layer of salt created by the acid wash. Ink that bears a high lipid content is then rolled over the surface. The water repels the grease in the ink and the only place for it to go is the cavity left by the original drawing material. When the cavity is sufficiently full, the stone and paper are run through a press which applies even pressure over the surface, transferring the ink to the paper and off the stone. Today, most lithography is offset lithography. This variation in lithography is used to produce books, newspapers, packaging, credit cards, and much more. The stone tablets are replaced with roughened but flexible metal or plastic plates.

Although offset lithography has become widespread, there are artists who still use the older process of lithography to create works of fine art. These artists have to master techniques like none other, from the temperament of the stone tablets to the many different methods of drawing. A recent renaissance in the lithography art form has made this type of art more popular then ever. Since you can create multiple prints from the same stone tablet, lithographs are often called "multiple originals." However, since the creation of these pieces take time and hard work, fine art lithographs are usually produced in very small editions.