The Corium & the Grain
Cowhide is made of two main integrated layers – the corium and the grain. Collagen fibers in the corium are thinner and more flexible, and become tighter and thicker as they move up toward the grain, where the fibers are tightly packed and very sturdy. The corium becomes thicker with age, which is why calfskins are thinner, smoother and softer than the hides of older animals.
The top part of the grain faces outward toward the hair, and can contain blemishes like insect bites, stretch marks, scars, and brands. This means that the very top part of the grain is often buffed off to make the leather look more uniform.
Types of Leather Grades
When the leather is corrected in any way, it is called top grain. Leather with the entire grain intact is called full grain. Full grain leather, even though it may have blemishes, is more expensive and more sought-after than top grain leather because of its durability and longevity. Both full grain and top grain leathers are referred to as grain leather.
There are three general categories: aniline, semi-aniline, and protected. Analine leathers are processed using soluble dyes to maintain their natural markings and texture, and do not have a surface pigment or coating. This makes them the most natural-looking leathers, but also more susceptible to scratching, fading and staining. Semi-analine leathers (like most bridle leathers) are treated with pigments and thus conceal more blemishes and have a more uniform coating, as well as staying more protected. Protected leathers have a non-leather coating sprayed or attached to the leather as a protectant.
FULL GRAIN LEATHER –comes from the top layer of the hide. It includes all the grain with it – hence the name full grain leather
TOP GRAIN LEATHER - Top grain is the second highest grade of leather. The surface is sanded to get rid of inherent imperfections. Pigmentation or staining gives the leather an attractive look.
CORRECTED GRAIN - also known as GENUINE leather, is produced using the skin layers that remain after the top is split off. Just like the top grain leather, it is also sanded to remove natural imperfections.
ANILINE LEATHER: This is the most natural leather with a minimal resistance to soiling. It requires regular upkeep.
SUEDE: is the most popular leather with a napped finish. It is used to make jackets, shoes, shirts, purses, and furniture.