Invented by Alois Senefelder in 1789, lithography (Greek “writing on stone”) is a method for producing printing forms for stone printing. Using special ink or chalk, the printing copy is transferred directly onto a smooth-ground block of carbonate of lime (calcium carbonate – CaCO3). The stone block is moistened before being inked up with oil-based printing ink. The printing areas then take up the oil-based ink, while the unchanged limestone repels it. The word lithographs (“lithos” for short) is also used colloquially for copy for offset printing (screened images, line engravings).