The variations of leather are all in the grade. Whether you’re in the market for a leather bag, a couch, or a pair of shoes, you’ll likely be faced with a half-dozen leather choices, each couched in careful marketing language. Full grain or top grain? Genuine leather or suede?
Each individual grade can come from the same hide; the difference is in how it’s split and finished. It helps to think of a hide like a sheet of plywood. The uppermost layer is the hair and epidermis. Then comes the grain, then the corium (or dermis). At the very bottom, you’ll find the flesh layer. The fibers of the epidermis and grain are more tightly bunched than those in the corium—they form the body’s protective covering, so they have to be tough.
A cow’s hide varies in thickness from about 1/4” to 3/8”—far thicker than the average leather jacket—so hides are nearly always split laterally and the layers shaved down to a uniform width. What you end up with is the grain (the top part of the hide with the hair scraped off), and the split (the fibrous layer that’s left once the grain is removed).
Hides were once split by hand with a sharp knife, a lengthy process resulted in much of the leather being wasted. In the 1850’s however, a pair of machines were invented to speed up leather production. The Union splitting machine, invented by Alpha Richardson, used a cylinder to turn the hide against a stationary blade. It not only split hides evenly and quickly, but could do so to an adjustable gauge. For splitting an entire hide, the belt-knife splitting machine (invented by Joseph Flanders and Jere Marden) was employed. It was a bigger and more complicated affair, with a high-speed revolving knife and rollers. With these machines, tanners were now capable of splitting an entire hide into 3-4 perfect layers.
Full Grain Leather
Full grain leather is considered the best quality money can buy. It’s made from the very top layer of the grain, where the fibers are the most dense, making it the most durable and water-resistant.
Because the surface of the leather hasn’t been mechanically altered, the natural grain, scars, insect bites and even brands are visible. The result is a very natural-looking material that tells the life story of the animal it came from. Too many scars and blemishes are considered unsightly, however, and so only the highest quality hides can be made into full grain leather.
Full grain leather is characterized by a smooth, supple hand. It will look more beautiful with use, as a patina is developed.
Corrected Grain Leather
Corrected grain is also known as top grain, as it’s still taken from the top layer of the hide. It’s essentially full grain leather that’s been shaved down, buffed and refinished to take away the scars and imperfections. This results in a more uniform finish, but because the durable top layer has been removed, corrected grain leather won’t last as long as full grain.
Often, corrected grain is embossed with a grain pattern after being shaved to give it a more natural appearance. Corrected grain leathers can also feel stiff, lacking the suppleness of full grain leather, and as they age they won’t show a lovely patina like full grain will.
Split Grain Leather
The split is the underlayer of the hide that is split off when the top grain was separated. Instead of a natural grain pattern, it has a more “suede-like” finish on top and bottom. The fibers are looser, resulting in a slightly stretchier material that’s not as strong or as durable as top grain leathers.
Split hides are perfect for garments, linings, handbags and anything that doesn’t need to withstand a lot of use. Some manufacturers will try to pass split off as top grain by embossing and refinishing the surface, but the resulting material is still thinner and less stable than top grain, and over time it will develop a matted look. The extra processing takes out the suppleness, as well.
Both top grain and split leathers can be finished in a variety of ways. Some of the most common include aniline, pigmented, nubuck, and suede.
Aniline refers to the way the leather is dyed. Full aniline leather has been dyed with transparent dyes that color the leather without concealing blemishes, but otherwise the natural characteristics haven’t been altered. Semi-aniline is finished with a thin top coat to protect from wear (detracting from the suppleness), and pigmented or protected leather has more processing and a heavier topcoat. It’s a durable finish, but it lacks the depth of color and texture that make pure leather a delight.
Nubuck and suede are both sanded or buffed to create a slight velvety nap on the surface. They have a similar feel, but nubuck is actually top grain leather that has been buffed on the grain side, whereas suede is taken from the split. Nubuck will have greater strength and thickness, along with a finer nap, since the fibers in the top grain are more tightly bunched than those in the split.
Blue in the center?
One last thing: when examining a leather product, try to find an unfinished edge. One hallmark of top-quality leather is that it will be the same color all the way through. Before hides go into the vats full of oils, preservatives and dyes, they’re a pale blue from the chromium salts used in the previous step. The tanning process can be expensive, and to cut costs, cheap tanneries often won’t let the hides sit in the vats long enough for the dyes and oils to fully saturate the leather.
Leading image: Swatches of vegetable tanned leather, a more environmentally friendly tanning process.