Lithography differs essentially from other printing techniques. It might be referred to as flat printing, since there is no relief between the printed parts and the parts that remain white. A drawing is made on a specific kind of resurfaced limestone with a greasy crayon or ink, and treated with gum arabic mixed with nitric acid. All rests on the play between the oil and water. The stone is carefully moistened with water on a damp sponge, and an oily ink is applied with a roller. Printing ink adheres only to the oil in the crayon, while the water on the other areas repels the ink. Paper posed on the inked stone is printed with a scraper bar that passes under pressure from one end to the other.
To obtain a print in several colors, one needs the same number of separate stones. Today, one uses often zinc plates onto which the drawing is transferred, using one of several possible techniques. These prints can be printed very efficiently and quickly on modern, sophisticated presses.