Kraft paper, also known as leather paper, is a paper material made from animal leather. Its main raw material is animal leather, usually cowhide. The process of making vellum involves chemically treating animal hides to separate the fibers and make paper. In this process, the leather is soaked, bleached, decomposed and fibrillated, resulting in a paper material that is flexible and durable.
It is important to note that the practice of making vellum may be restricted or changed over time due to environmental and animal protection concerns. In some cases, people may choose to use synthetic materials or other substitutes for paper materials similar to vellum in order to avoid the use of real animal leather.