Tanning refers to the process of treating an animal hide and turning it into leather. Without the tanning process, the hide will break down like any organic product.
The most common way of tanning leather is to use chromium sulphate, also known as chrome tanned.
Hides tanned with chromium sulphate tend to have good stain and water resistant characteristics. Chrome tanned leather will have a good thermal resistance and will retain its finished colour.