In general, leather is sold in these four forms
In general, leather is sold in these four forms:
Full-grain leather refers to hides that have not been sanded, buffed, or snuffed (as opposed to top-grain or corrected leather) to remove imperfections (or natural marks) on the surface of the hide. The grain remains allowing the fiber strength and durability. The grain also has breathability, resulting in less moisture from prolonged contact. Rather than wearing out, it develops a patina during its expected useful lifetime. High quality leather furniture and footwear are often made from full-grain leather. Full-grain leathers are typically available in two finish types: aniline, semi-aniline.
Top-grain leather (the most common type in high-end leather products) is the second-highest quality. It has had the "split" layer separated away, making it thinner and more pliable than full-grain. Its surface has been sanded and a finish coat added, which produces a colder, plastic feel with less breathability, and it does not develop a natural patina. It is typically less expensive and has greater stain resistance than full-grain leather if the finish remains unbroken.
Corrected-grain leather is any leather that has had an artificial grain applied to its surface. The hides used to create corrected leather do not meet the standards for use in creating vegetable-tanned or aniline leather. The imperfections are corrected or sanded off, and an artificial grain embossed into the surface and dressed with stain or dyes. Most corrected-grain leather is used to make pigmented leather as the solid pigment helps hide the corrections or imperfections. Corrected grain leathers can mainly be bought as two finish types: semi-aniline and pigmented.
Split leather is leather created from the fibrous part of the hide left once the top-grain of the rawhide has been separated from the hide. During the splitting operation, the top-grain and drop split are separated. The drop split can be further split (thickness allowing) into a middle split and a flesh split. In very thick hides, the middle split can be separated into multiple layers until the thickness prevents further splitting. Split leather then has an artificial layer applied to the surface of the split and is embossed with a leather grain (bycast leather). Splits are also used to create suede. The strongest suedes are usually made from grain splits (that have the grain completely removed) or from the flesh split that has been shaved to the correct thickness. Suede is "fuzzy" on both sides. Manufacturers use a variety of techniques to make suede from full-grain. A reversed suede is a grained leather that has been designed into the leather article with the grain facing away from the visible surface. It is not considered a true suede.[1]
Less-common leathers include:
Buckskin or brained leather is a tanning process that uses animal brains or other fatty materials to alter the leather. The resulting supple, suede-like hide is usually smoked heavily to prevent it from returning to a rawhide state, if wetted. It is easier to soften, and helps repel leather-eating bugs.
Patent leather is leather that has been given a high-gloss finish. Inventor Seth Boyden developed the original process in Newark, New Jersey in 1818. Patent leather usually has a plastic coating.
Fish leather is popular for its motifs and its pigmentation. Mainly used for making shoes and bags, the fish skin is tanned like other animal skins.[2] The species used include salmon, perch, sturgeon, etc.
Salmon : farmed in Iceland and Norway, salmon skin has fine scales. Its strength and elegant look make it the most popular fish leather.
Perch : from the Nile, its skin is recognizable with large, round and soft scales
Wolffish : smooth, without scales, with dark spots, and stripes due to the friction of marine rocks
Cod : finer scales than salmon, but more varied texture, sometimes smooth and sometimes rough
Sturgeon : known for its eggs (caviar), its leather is quite expensive
Eel : without scales, its skin is shiny
Tilapia : originally from Africa and farmed in many places, tilapia leather is beautiful, with resistant qualities similar to salmon and perch[3]
Shagreen is also known as stingray skin/leather. Applications used in furniture production date as far back as the art deco period. The word "shagreen" originates from France. It is known as the most difficult leather to work due to dished scales of the animal, and it is one of the most expensive leathers.
Shark is covered with small, close-set tubercles, making it very tough. Shark skin handbags were once in vogue, but interest has fallen as the material and production costs is very high. Moreover, this skin is more difficult to work. (Do not confuse with sharkskin, a woven textile product.
Vachetta leather is used in the trimmings of luggage and handbags. The leather is left untreated and is therefore susceptible to water and stains. Sunlight makes the natural leather darken in shade (develop a patina).
Slink is leather made from the skin of unborn calves. It is particularly soft and is valued for making gloves.
Deerskin is a tough, water-resistant leather, possibly due to the animal's adaptations to its thorny and thicket-filled habitats.[citation needed] Deerskin has been used by many societies, including indigenous Americans. Most modern deerskin is no longer procured from the wild, with deer farms breeding the animals specifically for the purpose of their skins. Large quantities are still tanned from wild deer hides in historic tanning towns such as Gloversville and Johnstown in upstate New York. Deerskin is used in jackets and overcoats, martial arts equipment such as kendo bogu, as well as personal accessories such as handbags and wallets.
Goatskin is soft but tough, and is used for items such as thorn-resistant gardener's gloves.
Nubuck is top-grain cattle hide leather that has been sanded or buffed on the grain side, or outside, to give a slight nap of short protein fibers, producing a velvet-like surface.
Russia leather is a particular form of bark-tanned cow leather. It is distinguished by an oiling step, after tanning, where birch oil is worked into the leather to make it particularly hard-wearing, flexible and resistant to water.
There are two other types of leather commonly used in specialty products, such as briefcases, wallets, and luggage:
Belting leather is a full-grain leather originally used in driving pulley belts and other machinery. It is found on the surface of briefcases, portfolios, and wallets, and can be identified by its thick, firm feel and smooth finish. Belting leather is generally a heavy-weight of full-grain, vegetable-tanned leather.
Napa leather is chrome-tanned and is soft and supple. It is commonly found in wallets, toiletry kits, and other personal leather goods.
The following are not "true" organic leathers, but are materials that contain leather fiber. Depending on jurisdiction, they may still be labeled as "Genuine Leather", even though the consumer generally can only see the outer layer of the material and can't actually see any of the leather content:
Bonded leather or reconstituted leather is an economical material that uses leftover organic leather (from tanneries or workshops) that are shredded and bonded together with polyurethane or latex on to a fiber sheet. The varying degree of organic leather in the mix (10% to 90%) affects the smell and texture. Its reduced cost makes it popular for furniture upholstery, especially for commercial furniture that requires durability—though durability can vary widely depending on the formulation.
Bycast leather is a split leather with a layer of polyurethane laminated to the surface and then embossed. Bycast was originally made for the shoe industry, and later adopted by the furniture industry. The original formula created by Bayer was strong but expensive. The result is a material that is slightly stiffer but cheaper than top-grain leather but has a much more consistent texture. Because its surface is completely covered in plastic, is easier to clean and maintain, but is not easily repaired.
From other animals
Phone cases in ostrich leather
Today, most leather is made of cattle skin, but many exceptions exist. Lamb and deerskin are used for soft leather in more expensive apparel. Deer and elkskin are widely used in work gloves and indoor shoes. Pigskin is used in apparel and on seats of saddles. Buffalo, goat, alligator, snake, ostrich, kangaroo, ox, and yak skins may also be used for leather.
Kangaroo leather is used to make items that must be strong but flexible. It is the material most commonly used in bullwhips. Some motorcyclists favor kangaroo leather for motorcycle leathers because of its light weight and abrasion resistance.[4] Kangaroo leather[5] is also used for falconry jesses, soccer footwear,[6] and boxing speed bags.[7] At different times in history, leather made from more exotic skins has been considered desirable. For this reason, certain species of snakes and crocodiles have been hunted.[citation needed]
Although originally raised for their feathers in the 19th century, ostriches are now more popular for both meat and leather.[8] Different processes produce different finishes for many applications, i.e., upholstery, footwear, automotive products, accessories, and clothing. Ostrich leather is currently used by many major fashion houses such as Hermès, Prada, Gucci, and Louis Vuitton. Ostrich leather has a characteristic "goose bump" look because of the large follicles where the feathers grew.
In Thailand, stingray leather is used in wallets and belts. Sting ray leather is tough and durable. The leather is often dyed black and covered with tiny round bumps in the natural pattern of the back ridge of an animal. These bumps are then usually dyed white to highlight the decoration. Stingray rawhide is also used as grips on Chinese swords, Scottish basket hilted swords, and Japanese katanas. Stingray leather is also used for high abrasion areas in motorcycle racing leathers (especially in gloves, where its high abrasion resistance helps prevent wear through in the event of an accident.)
Production processes
Drying of leather in East Timor
Leather tanning in Fes, Morocco
Tanned leather in Marrakech
Main article: Leather production processes
The leather manufacturing process is divided into three fundamental subprocesses: preparatory stages, tanning, and crusting. All true leathers undergo these subprocesses. A further subprocess, surface coating, can be added into the leather process sequence, but not all leathers receive surface treatment. Since many types of leather exist, it is difficult to create a list of operations that all leathers must undergo.
The preparatory stages are when the hide/skin is prepared for tanning. Preparatory stages may include: preservation, soaking, liming, unhairing, fleshing, splitting, reliming, deliming, bating, degreasing, frizing, bleaching, pickling, and depickling.
Tanning is a process that stabilizes the protein of the raw hide or skin so it does not putrefy, making it suitable for a wide variety of end applications. The principal difference between raw and tanned hides is that raw hides dry out to form a hard, inflexible material that, when rewetted (or wetted-back) putrefy, while tanned material dries to a flexible form that does not become putrid when wetted-back.
Many tanning methods and materials exist. The choice ultimately depends on the end application for the leather. The most common tanning material is chromium, which leaves the tanned leather a pale blue color (due to the chromium). This product is commonly called wet blue. The hides, when finished pickling, are typically between pH 2.8 and 3.2.[citation needed] At this point, tannery workers load the hides into a drum and immerse them in a float that contains the tanning liquor. The hides soak while the drum slowly rotates about its axis, and the tanning liquor slowly penetrates through the full thickness of the hide. Workers periodically cut a cross-section of a hide and observe the degree of penetration. Once the process achieves even penetration, workers slowly raise the float’s pH in a process called basification, which fixes the tanning material to the leather—and the more tanning material fixed, the higher the leather’s hydrothermal stability and shrinkage temperature resistance. Chrome-tanned leather pH is typically between pH 3.8 and 4.2.[citation needed]
https://en.wikipedia.org/wiki/Leather
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