Tanning involves combining the tanning agent and the hide protein to form a stable, durable, non-putrescible leather. The tanning processes are of two main types, vegetable tanning and mineral tanning.

Vegetable Tanning - In this case the hide is treated with vegetable tannins found in the bark and wood of certain trees. For centuries the bark of the oak tree was used as a source of tannin, but today a more common tannin is mimosa tannin found in the bark of various species of wattle tree.

Mineral Tanning - This tannage is commonly carried out with the aid of basic chromium sulphate, a mineral salt which penetrates the hide very rapidly, tanning being complete in twenty-four hours. The leather is a pale duck-egg blue in colour, and after suitable processing yields fine soft modern leather. Other mineral tannages (e.g. Aluminium Sulphate) are also used.