Step 1: Understand the Mezzotint process. Mezzotint is an intaglio printmaking process that involves systematically roughening a plate with a tool called a "rocker" to create a dense texture of pits and burrs that will hold ink and print a rich black. The image is then created by selectively smoothing and burnishing these areas to make them hold less ink and appear lighter.
Step 2: Consider the material properties needed. This process requires a metal that is soft enough to be worked by the rocker and burnishers but durable enough to hold the fine burr through multiple printings.
Step 3: Evaluate the options. Historically and traditionally, Copper has been the preferred metal for mezzotint because it has the ideal balance of softness for detailed work and hardness for durability. Zinc is generally too soft and does not hold the burr as well, while steel is too hard to work easily with the rocker.