Hardness testing and micro-hardness testing is used to measure the resistance of metals and materials to permanent change of shape when a force is applied. Hardness tests often measure the deformation caused to metals by indentation, but hardness testing may also measure resistance to cutting, scratching and abrasion. Methods of hardness testing include Knoop and Vickers micro-hardness testing, Rockwell standard testing, Rockwell superficial testing and Brinell testing.