The primary component of this material is a high resolution leather height map. It drives the following material properties:
Via Mix Map, I’m defining primary diffuse component of the material. The assumption here is that the deeper parts have had different impact from material production, processing, and use. Color dyes may have had less stress and UV exposure an have a slightly different hue.
I also use the leather height map to produce bump for the material. I mix it with procedural noise to introduce irregularities at much lower frequencies than the leather pattern.
The final Mix Map remaps the height map to a much smaller range to alter Reflection Glossiness channel. The assumption here is that the leather was quite rough and was later polished. The top surface had more polishing contact than cracked areas which remained rough. This is the opposite from a situation in which a leather wax compound us used to bring up the glossiness of the material. In those scenarios, wax is the coat that is responsible for the glossiness; it remains inside the leather cracks for much longer period as they are less accessible.