Graham “etching,” or processing, the surface of the stone with a mixture of gum arabic and nitric acid. A fresh drawing on a stone is generally processed or etched in two steps before it is ready to be printed. The aim of etching is to chemically separate the image and non-image areas of the drawing so that they will either accept or reject ink consistently. The first etch partially desensitizes the stone so that the drawing materials may be washed-out with solvent and replaced with ink during the roll-up process. The inked image is then given a second etch to complete the desensitization of the stone and form a durable base of ink-accepting and ink-rejecting areas during subsequent inking and printing.