A piece of (50×50) mm rubbing cloth (standard white cotton cloth), after conditioning in a standard atmosphere (temperature 20°C ± 2°C, humidity 65% ± 4%) for more than 4 hours, is placed flat on the rubbing head, ensuring the direction of the rubbing cloth aligns with the allowable direction of the rubbing head. The operation speed is one back-and-forth rubbing cycle per second, for a total of 10 cycles. The rubbing stroke on the sample is (104±3) mm, and the downward pressure applied is (9±0.2) N. After completing all 10 cycles, the rubbing cloth is removed, conditioned for more than 4 hours, and any excess fibers that may affect the rating are removed. As shown in the picture:
Color Fastness to Rubbing Tester