Tanning, or hide tanning, is the process of treating skins and hides of animals to produce leather. A tannery is the place where the skins are processed.
Historically, vegetable based tanning used tannin, an acidic chemical compound derived from the bark of certain trees, in the production of leather. An alternative method, developed in the 1800s, is chrome tanning, where chromium salts are used instead of natural tannins.