The term lithograph literally translated means “writing on stone”. It is a printing process that was invented in 1798 by Alois Senefelder of Munich. Most of the litho stones around the world came from a quarry near Munich. Generally the stones start out around 3 to 5 inches thick and vary in surface area from 4 x 5 inches to 4 x 5 feet. There are several basic grades of stone from what is called “yellow” (soft), to “blue” (hard), and in between are varying degrees of “tan”. Yellow stones are generally used for simple soft crayon drawings. The blue stones are prized for fine engravings. Tan stones are used for all types of drawings and engravings.
The most common type of lithograph used as fine art is drawn with a “crayon” or grease pencil and is occasionally combined with washes or solid painted areas. After the drawing is completed on the stone the entire surface is acid etched which makes the grease in the drawn image absorb into the stone and attract ink. The non-image area is treated by the etch so that it will attract water and repel the greasy ink. During the printing the stone is kept wet with sponges. When the ink is applied with a hand roller only the drawn image receives the ink. After inking the stone, paper is placed over the stone, then a backing sheet of heavy paper is placed over that as padding. Then a tympan, which used to be a thin sheet of metal but now is usually mylar or Plexiglas, is placed over the backing sheet.
The bed of the press that the stone lies upon actually rolls through the press. It is rolled into position under a scraper bar that is clamped down with great pressure upon the lead edge of the stone. The tympan is greased so that the scraper bar will slide as the bed of the press with the stone and paper is hand cranked under the scraper bar. Then the bar is released, the bed of the press is rolled back to the starting point, and the tympan, backing sheet, and paper are removed from the stone. This process is repeated for each print.
This is an over-simplification of the process. There are many preliminary steps required including grinding the stone to properly prepare the surface for drawing. After the drawing is finished there are applications of powdered rosin, talcum powder, nitric acid and phosphoric acid mixed with gum Arabic, asphaltum and lithotine or turpentine.
After the edition has been printed the image is partially obliterated in some way, usually a streak is removed with a fine pumice stone. Then one more print is made which is called a cancellation proof. This is a guarantee that no more prints will ever be made. The stone may be ground again to remove the entire image in preparation for a new drawing.
Stone lithographs can be printed in multiple colors, but each color usually requires a separate stone with the colors printed in succession. A more popular method of adding color is to make the initial print in black or some other dark color and then applying watercolor. All of Currier & Ives work was done this way. Many famous artists were well known for their lithographs as well as paintings, including Picasso, Whistler, Goya and Lautrec.