Imagery is drawn on a stone or aluminum plate with greasy materials (such as special crayons or ink) or toner (for plate lithography). The basic principle of lithography is that water and grease don’t mix. After chemically preparing the plate so that the image areas accept grease and repel water, the plate or stone is alternately sponged with water and rolled with ink, ensuring that the ink only sticks to the “grease loving” areas, reproducing the image as drawn.