Charbonnel Hard Black Ball Ground Our printers use wax grounds because they can be put on very evenly and are the most subtle and sensitive for line work. Hard ground is a combination of wax, tar and rosin. It resists acid. When heated, it is sticky and brown. It cures hard and stable. We apply the ground to the hotplate first and then transfer it to the plate. Once the swath of ground on the hotplate is smooth, we begin applying the ground to the surface of the etching plate. After coating your plate with a hard ground, you use an etching needle to break through it to expose lines that will etch when the plate is submerged in a solution of water and acid. Drawing through a hard ground requires no force; the acid does all the work. Because you are not cutting into the metal, the tool encounters little resistance, and your marks can flow with ease to create sharp, crisp lines and curves. Media Mail not available for this item.