Rohrer & Klingner Lithographic Crayons are made of wax, tallow, and Syrian asphalt and feature a high resistance against acids. They are a traditional drawing material that can be used directly onto stone litho plates and photo positive litho plates.
The crayons are available in six degrees of hardness (0-5), with No.0 being the softest, No.5 the hardest, and No.3 the most commonly applied lithographic crayon. Drawing with the hard crayon results in lighter, fine lines, especially when a smooth stone is used, while the soft crayon produces dark and thick lines.