What is Leather?

Leather is an organic material made of tanned animal skin. All animal fibers (leather included) are proteins and made up of amino acids. Due to the nature of the material, it responds quickly to changes in the relative humidity (RH) of its environment as well as to the introduction of sulphur dioxide. The response to changes in relative humidity is characterized by a change in the dimension to the object and in its suppleness.

There are two primary methods for tanning leather: vegetable-tanning and chrome-tanning.

Vegetable-tanned leathers are tanned with materials that come from plants. These leathers are more supple and take tooling and decoration well. Almost all leather book bindings are made of vegetable-tanned leathers.

Chrome-tanned leathers are produced using chromium salts. These leathers are very durable, both physically and chemically. They are difficult to work with and do not take tooling or decoration as well as vegetable-tanned leathers.