양피지, or "vellum," is a type of fine parchment made from the skin of animals, typically sheep or goats. It has been used for centuries in the creation of manuscripts, books, and important documents due to its durability and smooth surface, which allows for clear writing and detailed illustrations. The process of making 양피지 involves cleaning and stretching the animal skin, then treating it to create a smooth, white surface. This material was highly valued in the past, especially during the Middle Ages, for its ability to withstand the test of time, making it ideal for preserving important texts and artworks.