When the tightness is constant, the stiffness increases with the cube of thickness; when the quantity is constant, the stiffness increases with the square of thickness. Thickness can be increased through the following ways:

(1) Reduce beating degree and increase loose thickness of paper.

(2) Using high-thickness fiber raw materials.

(3) Reduce the pressure of pressing and pressing.

(4) Reduce the tension of drying net before drying.

(5) Reduce the use or non-use of fillers.

However, the application of these measures will inevitably have some negative effects, such as the roughness of the paper surface, affecting the fineness of the film and printing.