During the tanning process, a hide is split into layers and the top layer is referred to as the top grain. This is the most durable part of a leather hide due to the strength of the fibers. Dyes are usually tumbled with the hides in a large drum. The word aniline is an industry term for transparent dyes that are used to color hides. A very thin layer of polyurethane seals the hide and either an oil or wax finish is applied as a protectant against spills and light scratches.
Sunlight is a natural bleaching agent.
Any natural substance will be affected adversely by the sun. Heat draws the natural moisture out of the hide and can cause the skins to crack or become ashy. The application of a leather conditioner can reduce these reactions. 55 square feet. There are several variables that determine the size of a hide.