Tawing with alum
Tawing with alum - Alum tanned
Tawing is a method of tanning with aluminium salts (alum). It is a naturally-occurring double salt, but which is also artificially produced. Tawing comes under mineral tanning and is one of the oldest tanning processes. After tanning with alum, the dried leather is stiff and firm. To make it softer, the leather is then tumbled and greased.
Alum tanning makes the leather white and very water-sensitive. The tannins are washable, making this leather much more sensitive than with chrome tanning which, with a few exceptions such as for Sheepskin, has replaced alum tanning.
Alum tanning: Cricket ball from England.
Glacé tanning is a form of traditional white tanning and is based on natural ingredients. These include alum (aluminium sulphate), salt, egg yolk, wheat flour, fats and water. The tanning itself is a very short process, which takes only a few hours.
Nowadays glacé leather is described, when the tanning method is not clear. Leather with "glacé effect" is also offered. In such cases, the tanning method is then deviated. It's generally not clear what is meant by "glacé effect".
Glacé gloves are very sensitive to water due to the non-permanent, washable tanning. The ring finger of this glove was irreparably damaged by moisture.
Alum designer leather jacket from Italy with water stains on the back from 2017. The stains cannot be removed.
- Tanning leather
- Mineral tanning
- Chrome tanned
- Vegetable-tanned leather
- Synthetic tanned
- Tanning with fats and oils
- Chamois leather
- Brain tanning
|Chrome tanning - Vegetable-tanned leather - Synthetic tanning - Tanning with fats and oils|