A brief description of the tanning process

The Tanning process makes animal skins water and decay resistant. Protein fibres are converted into leather fibres - a process, which cannot be imitated synthetically. Apart from the quality of the raw material the kind of tanning is also decisive for the quality and the characteristics of the final product. Firmness, stretching ability, water resistance and also the surface characteristics such as durability or flexibility are decisively influenced by the tanning process. The traditional tanning methods are very old and can by subdivided into three different categories.

Bark or red tanning is made with vegetable agents (extracts from barks wood, leaves and fruits) and is used for heavy cattle hides. Bark tanning produces a very firm, durable and robust leather which gets its patina by usage.

Chamoising is produced by using cod liver oil and fat liquid agents predominantly for deerskin, doeskin, sheepskin and goatskin. Chamois treated leather is extremely soft, almost of woolen nature and can often be washed without suffering any damage.

Alum or white tanning is a mineral tanning, which works with alum stone and is mainly used for small animal skins and produces light and very soft leather.

Chrome tanning is also mineral and is of more recent date. It was introduced in the 19th century, and works with chrome and other mineral salts and has the advantage of very short tanning times. The result is very smooth, soft and cloth-like leather, which can be easily processed and which is very popular today.

These three basically different tanning processes are being used in a number of combinations and the tanning times are clearly shortened by mechanical and chemical means.

Leathers tanned with vegetable tanning agents are generally referred to as vegetable tanned. They are manufactured by drum tanning, colour pit or tan pit tanning, in processes which, in this order, together with increasing manufacturing time produce leathers, which become tougher and more durable. During the drum tanning process leather is tanned with vegetable tanning agents in a rotating drum within a comparatively short time. The leather becomes quite soft. Leather tanned with the special vegetable method in a so-called colour suspender - a system of 6 to 12 pits filled with tanning liquid - is called pit-tanned. Leather, which is really tanned for many months in a pit is called tan pit tanning.