In the textile sector, tanning activities are the physical and chemical processes of the leather and making it usable. Leatherwork is an art that has been maintained since ancient times. Modern leather industry in our country started with the tannery established in Beykoz Creek during the period of Mahmud II. Here, leather is produced to meet the army's need for shoes. During the War of Independence, this facility also provided the army's need for shoes. Cattle and sheep skins are used in leather production.

The chemical structure of the skin is 55 carbon, 25 oxygen. The rest are elements such as hydrogen, nitrogen, sulfur, phosphorus and iron. Biologically, percent 65 is water and percent 33 is protein. It is necessary to protect the skin from microorganism activities in the time it takes to process raw leather as finished leather.

It is very important to adjust the leather to the desired thickness between the mechanical processes performed during the production of a certain type of leather. If the desired final thickness of the leather is very different from the thickness measured after tanning, the thickness of the leather is adjusted. If the thickness differences are too small to be evaluated technically, the skin is immediately shaved. With this process, the remaining parts above the desired thickness setting is shaved and discarded. Dry shaving is a process of adjusting the thickness of the treated leathers to a standard shape.

The tensile, tear and elongation strength of the skin, as well as its thickness, vary according to the species and body regions of the animal. In addition, skin weight, skin size and skin thickness increase with the age of the animal.

Tests are carried out by authorized laboratories to determine the thickness of the skin within the scope of specific tests. The standards used in these tests are as follows:

• ISO 2589 (IULTCS / IUP 4) Skin - Physical and mechanical tests - Determination of thickness