Determine the fiber direction of paper
1. Why is there a fiber direction? Handmade paper, such as rice paper, Japanese paper, etc., does not necessarily have a clear fiber direction. However, in the paper made by modern machines, the reel of the machine is propelled in the same direction during the production process, and thus the direction of the fiber is generated. 2. Why is it important to correctly judge the "fiber direction"? Because paper or cardboard absorbs moisture from the air, tension is generated, and the direction of the tension is along the fiber direction. Imagine that if the various paper materials that make up a book are not in the same fiber direction, they will be subjected to different directions of tension produced by different materials, which will seriously affect the life of a book. Even a book that is extremely beautifully framed, firmness and practicality are still the first considerations. 3. How to judge? (1) Drowning method Take a little bit of water on either ...