From animal hide to leather

Animal skins consist of three layers. Starting from the outside of the skin, these layers are the epidermis, the dermis and the sub-cutaneous layer or tissue.
The epidermis constitutes only around 1% of the thickness of the skin and this layer is in contact with the outside world, and it has hair, fur, follicles, sweat glands etc. attached to it. The layer is removed in the process, as it is not used by others than furriers.
The dermis is the central layer, which is also the thickest. It constitutes around 85% of the total thickness of the skin and it is the layer used for making the leather. This layer contains living cells, which are structured into tight connective tissue. When it comes to tanning, there is a distinction between the upper part of the dermis, touching the epidermis, and the lower part of the dermis. The upper part is called grained leather and the lower part is called the split.
The sub-cutaneous layer consists of fat and loose connective tissue, and this part is in contact with the muscles of the animal. This layer is also removed in the process of making leather.

In order to preserve the hides and skins, they are cured. In the process of curing, any water from tissues is removed to slow down the process of decomposition, and up to 10% of their weight in water might be lost in this process. The hides and skins are stored in places, where the temperature is held around 10[Symbol]C and with a humidity between 70% and 90%. A couple of weeks later, the skins and hides are all inspected individually and sorted on the basis of different categories and demands.

After this, the skins and hides reaches the tannery. Here, the skin undergoes five processes prior to the process of tanning. The first out of these five processes is soaking, where the skin or hide is rehydrated and where impurities and such are removed. The second is unhairing and liming, where all animal hairs are removed. In the third process, fleshing, the sub-cutaneous layer is removed. The fourth stage, bating, involves softening the leather, and the fifth stage is called pickling, where the skin is acidified in order to prepare it for tanning.

The next process is the tanning process. Here, the skins and hides are turned into leather, using tannins. The tanning process turns the skin into a water-resistant, rot-proof material with a low water content. Afterwards, the leather undergoes mechanical procedures, which consist of shaving, sammying (removing any additional water) and setting-out (stretching and correcting defects of the leather) as well as different chemical procedures, which gives it its color, fullness, suppleness etc. Subsequent to this, the leather is dried. Lastly, the leather is treated with a certain finish, which depends on the purpose of the leather. These types of finish include aniline finish, semi-aniline finish and pigment finish.
In order to obtain a beautiful piece of high-quality leather, the hides and skins have to undergo all these different steps and procedures. When purchasing leather, you are ensured that the material has undergone several procedures in order to be used for many different purposes.