Leather Terminology
Full grain, aniline, drum dyed, vegetable-tanned. What is this nonsense? If you’ve never encountered these terms under a listing for a bag or a belt online shopping, you’re not alone. Let’s talk about leather.
Tanning:
Vegetable-Tanned vs. Chrome-Tanned
Chrome-Tan:
-Chrome-tan will not shine up with age or deepen in color- this could be a good thing in some cases but inevitably shows wear in unsavory ways most often. Knicks in the leather leave very little options for repair, and edges cannot be burnished. Instead, edge paint is used or the edge is left exposed. This also means that any kind of stamping requires a great amount of heat, not just pressure, and it cannot be wet-molded.
-Very much prone to stretching and ripping, and typically softer in temperament. Responds much better to water exposure, but I would still recommend against the washing machine and especially the dryer.
-No earthy “leather” smell! Usually chrome-tan has no odor at all, and sometimes it even has a very “chemical-like” smell.
This is what it’s all about.
Historically, leather was produced by treating the skin of an animal with a tannin, an acidic chemical compound derived of certain tree barks, to permanently restructure the protein structure. This is known as vegetable-tanned. A major innovation in the industrial revolution of the 1800s was the application of chromium salts in the tanning industry. This has grown to replace traditional vegetable-tanned leather, and now 90% of the leather produced worldwide is chrome-tanned. Chrome-tanning is much cheaper, much faster (in some cases production is a single day), much easier to dye for a wide range of colors, and therefore much easier to scale to mass production. Vegetable tanning can take 1-6 months, requires a large amount of water, and is generally a stubborn material to finish or dye.
So what are the pros and cons?
Veg-Tan:
-Because of the natural, less aggressive tanning, natural oils are retained in the leather and the protein structures allow for burnishing. This means that with wear, the leather develops a shine and deep patina. This also lends to repairability.
-Veg-tan is much stronger, less prone to stretching, less prone to ripping.
-Veg-tan does “tan” in the sun and the color will change and develop over time.
-It is often less water resistant than chrome-tans and this is actually why veg-tan is typically not used in shoe soles, watch strap linings, or upholstery. You absolutely cannot put it through the washing machine.
There are certainly uses for both, but Mooney Leather Goods primarily uses vegetable-tanned leathers and specializes in traditional veg-tan craftsmanship. This sets MLG apart from all department store soft goods, and even from the vast majority of designer brands. There is much, much more to be said of our leather, and I will try to get into the nitty gritty as clearly and effectively as I can below.
For a deeper dive…
Vegetable-Tanned
Leather tanned using traditional, natural tannins derived from certain tree barks; yields a more durable leather that is more nuanced and natural in appearance than the more common chrome-tans. This is the specialty and focus of Mooney Leather Goods.
Chrome-Tanned
The most common tannage — Leather produced using chromium salts. A softer, more supple, and more water resistant leather that is best suited for articles exposed to consistent moisture such as shoe linings and soles, watch strap linings, belt linings, or even bags intended for heavier use. It cannot be wet-formed or burnished, is much more difficult to repair, and will not develop a shine or darken with age.
Mineral-Tanned
Similar to chrome-tanned in the sense that chrome tanning is a subcategory of mineral tanning. Mineral tanning refers broadly to harsh chemical processing typically used in mass production tanneries, with salts derived from chromium, aluminum, or zirconium.
Combination-Tanned
Leather tanned with a combination of mineral salts and vegetable tannins. This can give the article benefits from each particular tan and makes for really unique and nuanced hides. Mooney Leather Goods uses a combination tanned leather lining in our classic bifolds, as the interiors are exposed to far less wear and tear and the flexibility of a more complicated tan allows for thinner, more flexible material for pockets.
Oil-Tanned
Oil-tanned leather is leather that goes through most of the chrome-tanning process, and then is impregnated with oils, creating a softer, waxier leather with a distinct rustic pull-up effect and significantly increased water resistance.
Full Grain
The highest quality part of a hide, the least processed. Made from the entire top layer (exterior surface) of the hide, retaining all natural markings and texture.
Top Grain
Made from the top layer of the hide, but may have some minor imperfections removed during processing.
Genuine/Composite/Bonded/Bycast
Also known as leatherette, imitation, PU, or vegan leather. These are all terms for faux leather, though some of this terms refer to a particular manufacturing method or process. Some of these take shavings of leather produced as a byproduct of higher quality articles such as suede, top grain, or full grain leather, and reconstitute them into a sheet with a faux “top grain” applied over the surface. Other variations involve shining up the surface of the composite sheet to mimic full grain leather or applying a faux surface to fabric. As far as Mooney Leather is concerned, they’re all the same- you’re safe from all of them here.
Aniline
Aniline leather undergoes minimal processing, with only transparent or translucent dyes used for coloring, allowing the natural grain, pores, scars, and other natural variations of the hide to remain visible. This is typically done with high-quality hides to showcase the quality of the hide, as any surface imperfections will be visible.
Semi-Aniline
Semi-aniline leather is dyed with a slightly pigmented dye, obscuring some (but not all) of the natural characteristics of the hide. This finish provides added surface protection compared to a fully aniline finish, giving the grain added resistance to staining and wear. Semi-aniline leather will patina with age, but as the grain surface has a light coating it will not be as dramatic or deep a patina as fully-aniline leather. Handbags, upholstery, and shoes often feature semi-aniline leather for it’s balance of natural appearance (although slightly reduced), soft temper, more uniform finish, and slightly increased resistance to wear.
Pigmented
Pigmented leather is sprayed with pigments, completely obscuring the natural qualities of the hide. This is typically done on lower quality hides, with imperfections too great or too numerous to make good aniline or semi-aniline leather. This method gives the grain a completely uniform appearance and much greater resistance to staining and color change over time. As the grain surface is completely obscured, pigmented leather does not develop a shine over time and any changes in the surface are beyond what I can repair.
Suede
A top-grain or split chrome-tanned leather with a napped (or buffed), cloth-like, velvety surface. Suede is the byproduct of full grain leather.
Nubuck
Similar to suede, but with a much more finer and softer finish. Nubuck is a top/full grain leather with the surface very lightly buffed off, utilizing the denser fibers of the full grain leather to achieve a much more velvety, finer nap.
Cordovan
Leather produced from horses. Known for its denser protein structures, the hide from the horse’s rear is known as the shell and is a very valuable, high quality leather popularized in the United States by Chicago’s own Horween Leather. The denser fibers of shell cordovan allow for very high polish finishes, making it popular in small accessories and high-end shoemaking.
Calfskin
Leather produced from bovine calves, typically softer, smoother, and “buttery.” Commonly used in garments and upholstery.
Chevre
Leather produced from goatskins— yielding a smaller, softer, and thinner article typically used in linings.
Shearling
Leather made from a recently sheared sheep, so the fur is not very long.
Chamois
Sheep leather, typically oil-tanned and often used in garments due to its soft, supple temper.
Milled Grain
Milled grain leather refers to a type of leather where the surface grain pattern is intentionally emphasized through a milling process, often involving tumbling the leather in a drum with water and heat. This process softens the leather and creates a distinct, often pebbled or textured, surface.
Embossed Leather/Corrected Grain
When a hide has damaged or imperfect grain, a textured finish can be applied by hand to replace or cover imperfections- this is corrected grain, as opposed to a naturally formed grain texture. Embossed leather is a term typically used to refer to a hide treated to mimic that of another leather (crocodile/alligator being the most common) or with a scroll design or geometric pattern.
Pull-Up Effect
Pull-up leather is a type of full-grain leather that's been treated with waxes and oils. It's known for its unique color-changing effect when stretched or bent, creating a lighter-colored, almost crackled appearance in those areas. This effect is caused by the displacement of the oils and waxes on the surface when the leather is manipulated.
Glazed Finish
A (grain) surface treatment resulting in glass-like high polish using friction and pressure to retain visibility of the natural grain features beneath.
Buffed Finish
A finish creating by lightly abrading and brushing the surface of a hide. While it is true that suede and nubuck have a buffed finish, this term is usually used to describe this finish outside of the perimeters of suede or nubuck. For example, a crocodile leather that has been gently buffed would not be described as suede or nubuck.
Waxed Finish
A surface treatment where a coating of wax is applied to the surface of a leather to increase its water resistance and protect the exterior from scratching or other kinds of wear. This is typically a clear wax, but there are leathers where the wax is opaque and in this case the finish serves all the same purpose but surface wear and tear will be much more noticeable. This is intentional and is a unique way to showcase individual wear cases.
Hot-Waxed/Wax-Stuffed/Heat-Stuffed
The process of applying oils or waxes to a hide and then exposing it to heat, impregnating the hide with oils. This gives the hide a more soft, supple feeling and an increased resistance to moisture.
Split Leather
Leather that is split from the exterior full grain. For example, full grain is the top or exterior of the hide, to reduce weight a layer under that is split from it, and that becomes suede or top grain.
Weight
In the leather industry, "leather weight" actually refers to thickness, not actual weight, and is typically measured in ounces, with 1 ounce equaling 1/64th of an inch.
Edge-Painting
The process of painting exposed edges on a finished leather item. There are a variety of methods to do this— sometimes a thickening agent is used to apply a thick layer in one application that is then smoothed using a heated tool. Another method is to apply multiple thinner layers, sanding the surface to even out imperfections between each application. Because chrome-tanned leathers cannot be burnished, this is most often seen on chrome tanned leathers and synthetics. Any kind of edge finishing greatly increases the longevity of the item, as it protects the interior fibers of the hide from moisture.
Burnishing
The process of polishing the edges of a finished leather item through friction, bringing the natural oils to the surface. Only vegetable-tanned leathers can be burnished. This is the preferred edge treatment by Mooney Leather Goods, as it is much easier and less invasive to repair an edge that over time will inevitably wear regardless of its finishing.
Edge Beveling
The process of cutting a small bevel on each side of an exposed edge of a leather item. This is done for a rounder profile, less likely to fold or tear. This is done in preparation for burnishing or edge painting.
Skiving
The process of removing some material from a cut piece of leather to reduce weight when the piece is assembled or blend the thickness of two pieces together.
Folded-Edge/Turned Edges
The process of skiving an edge and folding it over itself to hide the interior fibers of the hide. Another form of edge treatment.
Chiseling/Pricking
Chiseling is the process of hammering holes for a stitch line into an assembled leather item as leather is too thick and rough a material to stick with a needle. This is done with a maul and a sharp fork-like chisel. Pricking, alternatively, is the process of using a fork-like tool of softer materials to mark where each stitch hole will need to be for the purpose of later puncturing each mark with an awl while stitching.
Saddle-Stitching
Saddle stitching is the traditional hand stitch used in leather working. It requires two thick needles, both hands, and a lot of very precise tension applied to each stitch by hand. It is often done using a stitching pony- a wooden tool clamping the item while it is being stitched.