2. Tanning and Dyeing
It's a process which makes leather flat.
<Leather>
Skins and leather: "skin" becomes "leather" after it goes through a tannage process.
Animal leather is supposed to be the best material for footwear because of its breathability, softness, elasticity and resilience.
<Tanning>
Tanning is the process to treat animal skin chemically with a tanning formula, which makes it into leather.
There are vegetable and mineral tanning materials. A vegetable tannage uses tannin extract, which occurs naturally in a variety of tree barks. Mineral tannage uses a chemical called chromium sulphate.
<Dyeing>
Dyeing is a process which colors tanned leather.