The TAPPI T 549 standard specifies a method for measuring the static and dynamic coefficients of friction of uncoated writing and printing paper by a horizontal method. This method evaluates the friction characteristics of the paper surface in contact with the Miscellaneous surface by measuring the frictional resistance on the horizontal plane. The static coefficient of friction reflects the resistance of the paper at the beginning of sliding, while the dynamic coefficient of friction indicates the continued friction during sliding. These frictional characteristics are crucial for the printing performance of the paper, the smoothness of the processing process, and the experience of using the final product.