The drawing medium used to make a lithograph is an oil-based, greasy material such as lithographic crayons or chalks, lithographic pencils, rubbing crayon, and liquid drawing ink known as tusche. These materials contain grease, tallow, beeswax, or similar substances that allow the image to be drawn directly onto a polished stone (usually limestone) or a prepared metal plate. The grease content in the medium is critical because it repels water but attracts the oil-based printing ink during the lithographic printing process. The design is chemically fixed on the stone or plate through a reaction involving gum arabic and other treatments before printing. In summary, the key drawing media for lithographs are:
- Lithographic crayons or chalks
- Lithographic pencils
- Rubbing crayons
- Liquid drawing ink called tusche
These greasy materials enable the unique planographic printing process of lithography by interacting with water and oil-based inks to produce the printed image.
