Skins and hides are rarely used in their natural state as they are subject to rotting and temperature variations (hard and rigid when the temperature is low, soft and flaccid when it is high). The purpose of tanning is to eliminate these problem susing suitable agents of animal, vegetable, mineral or synthetic origin.
Structure of the hide
Starting from the putside, the skin (or hide) has three layers :
The epidermis and everything attached to it - hair, fur, follicles, sebaceous and sweat glands, horney, material etc. - is usually eliminated as it is not used except by furriers.