Leatherworking A to Z: General Leather Terms to Know

Just like with any new skill, there’s a lot to learn when you’re getting into leatherwork. What tools do you need? How do you use them? What are the different kinds of leather? With so many new terms, it’s hard to keep it all straight. But don’t worry — our blog series, "Leatherworking A to Z" is a glossary of important and well-known leatherworking tools, techniques and terms. Scroll on through to discover all the leather terminology you need to know.

General Leather Terms

Aniline Dyeing — Aniline dyeing is a process that uses a dye to stain a hide through immersion rather than a pigmented coating; this kind of dye preserves the natural characteristics of the leather. Aniline dyeing is typically done on full grain leathers, as it preserves the natural color of the hide but imparts no additional color.

Corium — This is the thickest layer of a leather hide. The fibers in this layer of the hide tend to be looser, which is why suede has a longer nap than nubuck, which is abraded from a top grain layer.

Hide — A leather hide is the full skin of an animal, which has been tanned. A hide includes the grain – the outside surface of the skin – which can be corrected or left with imperfections, and the flesh side, where the skin was separated from the body of the animal. Hides can be purchased as a whole or cut to more manageable sizes. Whole hides average between 45-55 sq. ft. of usable leather.

Irons — This is an old unit of measurement that refers to leather thickness, commonly used by cobblers. Irons are measured in 0.75 increments; 0.75 irons equals 1/64-inches and 1 ounce of leather thickness.

Leather Temper/Hand — This refers to how soft or pliable leather is. Firm leathers are good for sturdy things like belts; a medium leather is good for bags; soft leather is good for upholstery or garment-making. There is no direct correlation between leather weight and leather temper; heavier leathers will not necessarily all be firm, and lighter leathers can be firm or soft.

Leather Weight (oz.) — Given in ounces, "weight" refers to how thick a piece of leather is; in theory, the number reflects what one sq. ft. of leather should weigh. One ounce of leather is equivalent to 0.4mm and 1/64-inches of thickness.

Patina — Much like waxed canvas, as leather ages and wears it will develop a rich, marbled look and shine that adds character to your leather goods. This character is called "patina." Patina does not mean your leather is worn, just that it has aged with use. Full grain, vegetable tanned leather is known for developing the best patina. Heavily treated or lower quality leather won’t wear as well and so won’t age as nicely.

 
This wallet shows how the leather has changed with use.

Tanning

Alum Tanned Leather — This is a tanning method using aluminum salts that results in very light colored or white leathers. Alum tanned leathers are stiffer than vegetable or chrome tanned leathers, and are incredibly water sensitive.

Chrome Tanned (chrome tan) — Chrome tanning is a quicker process than vegetable tanning that results in softer, more pliable leather. The "chrome" refers to the chromium compound used in the tanning process instead of tannins. This is the most widely used tanning method for commercial leather production. Chrome tanned leather is too soft to tool or stamp. Good for upholstery and garment leathers.

Oil Tanned — This does not refer to an actual tanning or hide preservation method. Oil tanned leathers are (usually) vegetable tanned leathers that are imbued with specialty waxes and oils during or after the tanning process. This results in a soft, durable and weather resistant leather. Oil tanning results in pull-up leather.

Tanning — Tanning is the process that chemically alters the protein structure of animal skin, making it more durable and less decomposable. Tanning can also include the addition of dye.

Tannins — Tannins are natural compounds derived from plants. The most common sources of tannins used in tanneries to make leather are chestnut, oak, hemlock, mangrove and acacia trees. Tannins produce natural shades such as browns, beiges and reds.

Vegetable Tanned (veg tan) — This tanning process relies on the natural tannins found in certain plants and trees to alter the proteins of the animal skin. Commonly used plants include chestnut and oak trees. Hides are stretched onto frames and submerged in a vat of tannin-containing liquid. Veg tan leather is not very flexible on its own, but vegetable tanned leathers can then be treated or "stuffed" with oils and waxes to increase pliability. Untreated veg tan leather is ideal for stamping and tooling due to its rigidity.

Types of Leather

Bonded Leather — To create bonded leather, leather scraps are shredded and reformed into sheets that are then embossed to look like full or top grain leather, or other animal leathers. Bonded leather technically contains actual leather, but is less durable than any other form of leather.

Bridle Leather — This is vegetable tanned leather infused with oils and waxes that penetrate all the way through the hide. This gives the leather weather resistance as well as a smooth, supple feel on both the grain and flesh sides of the hide.

Full Grain — Full grain is the most premium cut of leather. It is the full, unmodified surface skin of the animal. Full grain leather will have blemishes and marks of the animal's life, including bug bites, branding or scars. You can have full grain leather of various thicknesses or weights, as leather is skived or split from the flesh side.

Full grain leather.

Hair-on Hide — This is leather that is tanned with the animal’s hair still on. Hair-on hides undergo a regular chrome tanning process and there is no functional difference between hair-on and hair-off chrome tanned leather. Hair-on hides can generally be used in any leather application: in belts, bags, wallets, furniture and more. The hair may wear or fall off with use and time, but the leather underneath is treated and can continue to be used.

Harness Leather — Harness leather is a kind of vegetable tanned leather produced with strength as the priority. It is infused with fewer oils and waxes than bridle leather to maintain the strength and stiffness of the fibers.

Latigo — This kind of leather is first chrome tanned, and then vegetable tanned. It is tumbled in drums to absorb various oils and waxes. It has characteristics of both tanning processes: the strength and durability of vegetable tanned leathers and the pliability of chrome tanned. Because of all the added oil, latigo leather is not suitable  for stamping or tooling. Latigo has a high water resistance and is ideal for outdoor applications.

Nubuck — Similar to suede, nubuck is leather that has been abraded to produce a soft, napped texture. Nubuck is made from top grain leather. Because the surface of nubuck is closer to the grain than suede, the nap is shorter. Nubuck tends to be stronger and more durable than suede, since suede is made from the corium layer of the hide where the fibers are looser. Nubuck, however, is made from the grain surface of a hide with tighter fibers.

Full grain leather compared to nubuck leather.

Pigmented Leather — Pigmented leathers are top grain leathers to which surface pigments and finishes have been added to conceal the natural markings and characteristics of the hide. The added finishes increase the durability of the leather.

Pull-Up Leather — Pull-up leather is an aniline dyed leather that is finished with transparent waxes and oils (oil tanned). This finish gives the leather a very soft hand and a shiny appearance. Because the leather has a high degree of stretch, it is especially suitable for high-end upholstery and furniture applications. Where the leather is pulled or stretched, the wax coating appears lighter in color than the rest of the hide. This gives the leather a worn-in and aged appearance.

Pure Aniline Leather — This refers to leather that has no added color and exhibits the natural markings and variations of the hide. Pure aniline leather is the highest quality of full grain leather hides available. Also referred to as "naked leather."

Rawhide — Rawhide is a type of leather that has been de-haired and partially prepared for tanning by soaking in lime, but has not been tanned. Rawhide tends to be brittle.

Semi-Aniline Leather — This refers to leather that has been aniline dyed but finished with a pigmented coating. This coating increases abrasion resistance and corrects imperfections in the hide so it features a more consistent color and fewer natural markings.

Split Leather — Leather is divided along an axis between the "grain" (top grain and full grain), and the "split," which will include the flesh side of the skin (and makes up the bulk of a hide). Leather is often split in the corium layer of the hide. Because the leather fibers are looser, split leather is not as durable as full or top grain leather, where the fibers are denser. There are several uses for split leather. Split leather can be treated and embossed to look like top grain leather, which is sometimes referred to as "genuine leather" or "embossed leather." Another use for split leather is suede.

Suede — Suede is produced from the underside of a split piece of leather. The corium surface  is abraded to produce a napped texture with a soft, velvety finish. The nap on suede is longer than nubuck because the surface of the suede is further away from the grain, where the leather fibers are looser. Suede tends to be soft, thin and pliable.

Full grain leather compared to suede.

Top Grain — The designation given to full grain leather when imperfections are corrected. Top grain leather has a surface that has been altered in some way, even minimally. It is not the same as full grain leather. Nubuck is top grain leather that has been split from the full grain and abraded to produce a napped finish.

Upholstery Leather — Upholstery leather is usually chrome tanned for pliability and aniline dyed. Lightweight leather, generally 2-3 oz., is ideal for most upholstery applications.