Lithography is a printmaking method in which the artist, using a grease-based medium such as a lithographic pencil or lithographic wash, draws on a lithography stone (or aluminum plate) as they would crayon on paper. Then, the stone or plate is etched with a mixture of gum Arabic and acid, desensitizing the surrounding stone to grease absorption. Before printing, the gum Arabic is removed using a damp sponge, and the stone remains wet throughout the printing process. The result is a matrix that builds up ink where grease was placed (the drawing on the stone), and resists ink where it is wet (the desensitized areas of the stone).