1.1 ,This test method describes the calibration or calibration verification of rotational viscometers in which the rotational element is immersed in a Newtonian reference material under ambient temperature conditions. The method is applicable to rotational-type viscometers where a constant rotational speed results in a measured torque generated by the test specimen, and to Stormer viscometers where a constant applied torque results in a measured rotational speed. It is not intended for cone-and-plate or parallel plate viscometers.