GB/T 1291-2025 is a special project standard for paper and Cardboard performance testing, which specifies the determination method of inks absorbency. The standard specifies the determination principle, required instruments, operation steps and result calculation and representation, and is suitable for ink absorbency testing of all kinds of paper and Cardboard. The standard can unify the industry detection method and ensure the accuracy of data. It provides a reliable technical basis for paper and Cardboard adaptability assessment in the printing field and product mass control, and helps to ensure the printing effect Stability.