Processing leather is a process that has been used for centuries to turn animal hides into leather. Tanning is the process of treating animal hides with tannins, which are acidic compounds found in plants, to preserve and soften the hide. The tanning process also helps to prevent the hide from rotting and makes it more durable. Tanning can be done by using natural tannins or by using synthetic chemicals. The end result of the tanning process is a soft, supple leather that is resistant to water and other elements.