May 17, 2006· Rockwell, Brinell, Mohs, and Shore hardness are not suitable for toner sheets. Rockwell hardness, for example, is used by a cone type indenter, while Brinell hardness is used by steel ball indenter with a diameter of 10 mm along with an additional load of about 3 t; these methods are not suitable for the measurement of materials with low hardness.