Leather raw materials from natural products. Leather processing requires much complicated and annoying work to accomplish all these chemical, mechanical and biological reactions. It needs chemicals to treat the protein, make it stable, and have the promise of property.
It needs machine or tools to treat the leather to be even and suitable area and thickness. It needs enzymes or bacterias to change or remain the characteristics of the skin.
In a small handicraft shop with two workers, or in a modern multi-million-dollar tannery, people can produce the same quality of leather. The only difference is productivity, stability or adaptability is not the same.