GB/T 460-2008 "Determination of Sizing of Paper" specifies two methods for determining the sizing of paper: the ink line method and the liquid penetration method. The former is applicable to cultural and writing papers, while the latter is suitable for white papers with lower basis weight. The ink line method defines the sizing degree based on the maximum width of lines without diffusion or bleeding on both sides, while the liquid penetration method evaluates the sizing effect based on the liquid penetration condition. The standard clarifies sample pretreatment, instrument requirements, and result calculation rules, providing a basis for evaluating the liquid penetration resistance of paper.