1. ALL ABOUT LEATHER:
Leather Info -
Leather is a material created through the tanning of hides and skins of animals, primarily cattlehide. The tanning process converts the putrescible skin into a durable, long-lasting and versatile natural material for various uses.
Leather is an important material with many uses. Together with wood, leather formed the basis of much ancient technology. The leather industry and the fur industry are distinct industries that are differentiated by the importance of their raw materials. In the leather industry the raw materials are by-products of the meat industry, with the meat having higher value than the skin. The fur industry uses raw materials that are higher in value than the meat and hence the meat is classified as a by-product. Taxidermy also makes use of the skin of animals, but generally the head and part of the back are used. Hides and skins are also used in the manufacture of glue and gelatin.
Forms of leather:
There are a number of processes whereby the skin of an animal can be formed into a supple, strong material commonly called leather.
Vegetable-tanned leather is tanned using tannin (hence the name "tanning") and other ingredients found in vegetable matter, tree bark, and other such sources. It is supple and brown in color, with the exact shade depending on the mix of chemicals and the color of the skin. Vegetable-tanned leather is not stable in water; it tends to discolor, and if left to soak and then dry it will shrink and become less supple and harder. In hot water, it will shrink drastically and partly gelatinize, becoming rigid and eventually brittle. Boiled leather is an example of this where the leather has been hardened by being immersed in hot water, or in boiled wax or similar substances. Historically, it was occasionally used as armour after hardening, and it has also been used for book binding. This is the only form of leather suitable for use in leather carving or stamping.
Chrome-tanned leather, invented in 1858, is tanned using chromium sulfate and other salts of chromium. It is more supple and pliable than vegetable-tanned leather, and does not discolor or lose shape as drastically in water as vegetable-tanned. It is also known as wet-blue for its color derived from the chromium. More esoteric colors are possible using chrome tanning.
Aldehyde-tanned leather is tanned using glutaraldehyde or oxazolidine compounds. This is the leather that most tanners refer to as wet-white leather due to its pale cream or white color. It is the main type of leather used in chrome-free leather often seen in infant's shoes and in automobiles that prefer a chrome-free leather. Formaldehyde tanning (being phased out due to its danger to workers and the sensitivity of many people to formaldehyde) is another method of aldehyde tanning. Brain-tanned leathers fall into this category and are exceptionally water absorbent. Brain tanned leathers are made by a labor-intensive process which uses emulsified oils often those of animal brains. They are known for their exceptional softness and their ability to be washed. Chamois leather also falls into the category of aldehyde tanning and like brain tanning produces a highly water absorbent leather. Chamois leather is made by using oils (traditionally cod oil) that oxidise easily to produce the aldehydes that tan the leather.
Synthetic-tanned leather is tanned using aromatic polymers such as the Novolac or Neradol types. This leather is white in color and was invented when vegetable tannins were in short supply, i.e. during the Second World War. Melamine and other amino-functional resins fall into this category as well and they provide the filling that modern leathers often require. Urea-formaldehyde resins were also used in this tanning method until dissatisfaction about the formation of free formaldehyde was realized.
Alum-tanned leather is tanned using aluminium salts mixed with a variety of binders and protein sources, such as flour, egg yolk, etc. Purists argue that alum-tanned leather is technically "tawed" and not tanned, as the resulting material will rot in water. Very light shades of leather are possible using this process, but the resulting material is not as supple as vegetable-tanned leather.
Rawhide is made by scraping the skin thin, soaking it in lime, and then stretching it while it dries. Like alum-tanning, rawhide is not technically "leather", but is usually lumped in with the other forms. Rawhide is stiffer and more brittle than other forms of leather, and is primarily found in uses such as drum heads where it does not need to flex significantly; it is also cut up into cords for use in lacing or stitching, or for making many varieties of dog chews.
Full-Grain leather or Top-Grain leather is referring to the upper section of a hide that contains the epidermis or skin layer. It refers to hides that have not been sanded, buffed or snuffed (otherwise known as Corrected) in order to remove imperfections on the surface of the hide. Only the hair has been removed from the epidermis. The grain remains in its natural state which will allow the best fiber strength, resulting in greater durability. The natural grain also has natural breathability, resulting in greater comfort for clothing. The natural Full-Grain surface will wear better than other leather. Rather than wearing out, it will develop a natural "Patina" and grow more beautiful over time. The finest leather furniture and footwear are made from Full-Grain leather. For these reasons only the best raw hide are used in order to create Full-Grain or Top-Grain leather. Full grain leathers can mainly be bought as two finish types: aniline and semi-aniline.
Corrected-Grain leather is any Top-Grain leather that has had its surfaces sanded, buffed or snuffed in order to remove any imperfection on the surface due to insect bites, healed scars or brands. Top-Grain leather is often wrongly referred to as Corrected-Grain. Although Corrected-Grain leather is made from Top-Grain as soon as the surface is corrected in any way the leather is no longer referred to as Top-Grain leather. The hides used to create corrected leather are hides of inferior quality that do not meet the high standards for use in creating aniline or semi-aniline leather. The imperfections are corrected and an artificial grain applied. Most Correct 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 that is created from the fiberous part of the hide left once the Top-Grain of the raw hide has been separated from the hide. During the splitting operation the 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. Splits can 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. Suede is less durable than top-grain. Suede is cheaper because many pieces of suede can be split from a single thickness of hide, whereas only one piece of top-grain can be made. However, manufacturers use a variety of techniques to make suede appear to be full-grain. For example, in one operation, glue is mixed with one side of the suede, which is then pressed through rollers; these flatten and even out one side of the material, giving it the smooth appearance of full-grain. Latigo is one of the trade names for this product. 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 a true form of suede.
Other 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 rotting.
Patent leather is leather that has been given a high gloss finish. The original process was developed in Newark, New Jersey, by inventor Seth Boyden in 1818. Patent leather usually has a plastic coating.
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 and is commonly confused with a shark skin and stingray skin combination.
Vachetta leather is used in the trimmings of luggage and handbags, popularized by Louis Vuitton. The leather is left untreated and is therefore susceptible to water and stains. Sunlight will cause the natural leather to darken in shade, called a patina.
Slink is leather made from the skin of unborn calves. It is particularly soft, and is valued for use in making gloves.
Deer Skin is one of the toughest leathers, partially due to adaptations to their thorny and thicket filled habitats. Deerskin has been prized in many societies including indigenous Americans. Most modern deer skin 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 NY. Deer skin is used in jackets and overcoats, professional sporting equipment such as kendo bogu, as well as high quality personal accessories like handbags and wallets. It commands a high price due to its relative rarity and proven durability.
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. There are two other descriptions of leather commonly used in specialty products, such as briefcases, wallets, and luggage. Nubuck is similar to suede, but its texture is finer. It differs in that suede is created from the inner side of a hide, whereas nubuck is created from the outer side of a hide, giving it more strength and thickness along with a fine grain. It is generally more expensive than suede, and must be coloured or dyed heavily to cover up the sanding and stamping process.
Belting leather is full grain leather that was originally used in driving pulley belts and other machinery. It is often found on the surface of briefcases, portfolios, and wallets, and can be identified by its thick, firm feel and smooth finish. Belting leather is the only kind of leather used in luxury products that can retain its shape without the need for a separate frame; it is generally a heavy-weight or full-grain, vegetable-tanned leather.
Nappa leather or Napa leather is extremely soft and supple and is commonly found in higher quality wallets, toiletry kits, and other personal leather goods.
The following are not 'true' leathers, but contain leather material.
Bonded leather or "Reconstituted leather", is not really a true leather but a man-made material composed of 90% to 100% leather fibers (often scrap from leather tanneries or leather workshops) bonded together with latex binders to create a look and feel similar to that of genuine leather at a fraction of the cost. Bonded leather is not as durable as other leathers, and is recommended for use only if the product will be used infrequently. Examples of products that are most commonly constructed with bonded leather are; Bibles, diaries, art books, desk accessories, hymnals, bags, belts, chairs, sofas, etc.
Bicast leather is a man-made product that consists of a thick layer of polyurethane applied to a substrate of low-grade or reconstituted leather. Most of the strength of bicast leather comes from the polyurethane coating. Bicast was originally made for the shoe industry and recently was adopted by the furniture industry. Most of the Bicast used today is created using inferior generic chemicals resulting in an inferior material. The result is a much stiffer product that tends to delaminate resulting in bubbles and cracking.
Leather from other animals:
Today, most leather is made of cattle skin, but many exceptions exist. Lamb and deer skin are used for soft leather in more expensive apparels.
Kangaroo skin is used to make items which need to be strong but flexible, it is the material most commonly used in high quality bullwhips. Kangaroo leather is favored by some motorcyclists for use in Motorcycle Leathers specifically because of its lighter weight and higher abrasion resistance compared with cowhide, thus providing greater protecting in case of a fall on the roadway. Kangaroo leather is also used for high performance soccer footwear.
Leather made from more exotic skins has at different times in history been considered very beautiful. For this reason certain snakes and crocodiles have been hunted to near extinction.
In the 1970s, ostrich farming for their feathers became popular, and ostrich leather became available as a side product. There are different processes to produce different finishes for many applications, i.e., upholstery, footwear, automotive products, accessories and clothing. Ostrich leather is considered one of the finest and most durable in the world and 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 from which the feathers grew.
In Thailand, sting ray leather is used in wallets and belts in the same way as regular bovine leather. Sting ray leather is as tough and durable as hard plastic. 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. Leather clothing is also popular in Thailand.
In the United States, bison leather has become popular. It is used for gloves, jackets and some baseball gloves. It is rugged but supple and has a waxy feel.
Overall, leather comes from a variety of other sources, including the skins of cattle, hogs, goats, sheep, alligators, ostriches, kangaroos, Yak.
There is quite a wide range of different animal leather used both for Leather garments as well as Leather Goods such as Ladies Handbags, Gents wallets, Ladies Purses, Leather Belts, File bags and other customized leather articles.
The most commonly used leather types are Cow leather, Sheep leather, Buffalo Leather and Ox leather. The most expensive is Cow leather and then Buffalo leather, Ox leather and Sheep leather respectively. The Sheep leather is quite famous for its softness and mostly used in leather garments; however due to certain restrictions of its overall size; it cannot be used for long coats and there Cow leather and Buffalo leather is widely used.
Leather production processes:
The leather manufacturing process is divided into 3 fundamental sub-processes: preparatory stages, tanning and crusting. All true leathers will undergo these sub-processes. A further sub-process, surface coating can be added into the leather process sequence but not all leathers receive surface treatment. It's difficult to have a list of operations that all leathers must undergo, as there are so many types of leather.
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 the process converts the protein of the raw hide or skin into a stable material which will not putrefy and is suitable for a wide variety of end applications. The principal difference between raw hides and tanned hides is that raw hides dry out to form a hard inflexible material that when re-wetted (or wetted back) putrefy, whilst tanned material dries out to a flexible form that does not become putrid when wetted back. There is a large number of different tanning methods and materials that can be used, the choice is ultimately dependent on the end application of the leather. The most commonly used tanning material is chromium, which leaves the leather once tanned a pale blue colour (due to the chromium), this product is commonly called “wet blue”. The hides once they have finished pickling will typically be between pH of 2.8-3.2. At this point the hides would be loaded in a drum and immersed in a float containing the tanning liquor. The hides are allowed to soak (while the drum slowly rotates about its axle) and the tanning liquor slowly penetrates through the full substance of the hide. Regular checks will be made to see the penetration by cutting the cross section of a hide and observing the degree of penetration. Once a good even degree of penetration exists, the pH of the float is slowly raised in a process called basification. This basification process fixes the tanning material to the leather and the more tanning material fixed the higher the hydrothermal stability and increased shrinkage temperature resistance of the leather. The pH of the leather when chrome tanned would typically finish somewhere between 3.8-4.2.
Crusting is when the hide/skin is thinned, retanned and lubricated. Often a coloring operation is included in the crusting sub-process. The chemicals added during crusting have to be fixed in place. The culmination of the crusting sub-process is the drying and softening operations. Crusting may include the following operations: wetting back, sammying, splitting, shaving, rechroming neutralisation, retanning, dyeing, fatliquoring, filling, stuffing, stripping, whitening, fixation, setting, drying, conditioning, milling, staking and buffing.
For some leathers a surface coating is applied. Tanners refer to this as finishing. Finishing operations may include: oiling, brushing, padding, impregnation, buffing, spraying, roller coating, curtain coating, polishing, plating, embossing, ironing, ironing/combing(for hair-on)and glazing.
Role of enzymes in leather production:
Enzymes like proteases, lipases and amylases have an important role in the soaking, dehairing, degreasing, and bating operations of leather manufacturing.
Proteases are the most commonly used enzymes in leather production. The enzyme used should not damage or dissolve collagen or keratin, but should be able to hydrolyse casein, elastin, albumin and globulin-like proteins, as well as non-structured proteins which are not essential for leather making. It is especially important to hydrolyse the elastin if the leather is to be limed, or treated with calcium hydroxide; if not treated properly before liming, the elastin will harden and the grain will be loose. .
Lipases are used in the degreasing operation to hydrolyse fat particles embedded in the skin.
Amylases are used to soften skin, to bring out the grain, and to impart strength and flexibility to the skin. This process is called bating.
Preservation and conditioning of leather:
The natural fibers of leather will break down with the passage of time. Acidic leathers are particularly vulnerable to red rot, which causes powdering of the surface and a change in consistency. Damage from red rot is aggravated by high temperatures and relative humidities, and is irreversible.
Exposure to long periods of low relative humidities (below 40%) can cause leather to become desiccated, irreversibly changing the fibrous structure of the leather.
Various treatments are available such as conditioners, but some of these are not recommended since they impregnate the structure of the leather with active chemicals, are sticky, and attract stains.
Ancient methods of tanning:
In ancient history, tanning was considered a noxious or "odiferous trade" and relegated to the outskirts of town, amongst the poor. Indeed, tanning by ancient methods is so foul smelling that tanneries are still isolated from those towns today where the old methods are used. The ancients used leather for waterskins, bags, harnesses, boats, armor, quivers, scabbards, boots and sandals. Around 2500 BC, the Sumerians began using leather, affixed by copper studs, on chariot wheels.
Skins typically arrived at the tannery dried stiff and dirty with soil and gore. First, the ancient tanners would soak the skins in water to clean and soften them. Then they would pound and scour the skin to remove any remaining flesh and fat. Next, the tanner needed to remove the hair fibers from the skin. This was done by either soaking the skin in urine, painting it with an alkaline lime mixture, or simply letting the skin putrefy for several months then dipping it in a salt solution. After the hair fibers were loosened, the tanners scraped them off with a knife.
Once the hair was removed, the tanners would bate the material (see below) by pounding dung into the skin or soaking the skin in a solution of animal brains. Among the kinds of dung commonly used were that of dogs or pigeons. Sometimes the dung was mixed with water in a large vat, and the prepared skins were kneaded in the dung water until they became supple, but not too soft. The ancient tanner might use his bare feet to knead the skins in the dung water, and the kneading could last two or three hours.
It was this combination of urine, animal feces and decaying flesh that made ancient tanneries so odiferous.
Children employed as dung gatherers were a common sight in ancient cities. Also common were "piss-pots" located on street corners, where human urine could be collected for use in tanneries or by washerwomen. In some variations of the process, cedar oil, alum or tannin were applied to the skin as a tanning agent. As the skin was stretched, it would lose moisture and absorb the agent.
Leftover leather would be turned into glue. Tanners would place scraps of hides in a vat of water and let them deteriorate for months. The mixture would then be placed over a fire to boil off the water to produce hide glue.
Variations of these methods are still used by do-it-yourself outdoorsmen to tan hides. The use of brains and the idea that each animal (except buffalo) has just enough brains for the tanning process have led to the saying "Every animal has just enough brains to preserve its own hide, dead or alive."
Modern methods of tanning:
The first stage is the preparation for tanning. The second stage is the actual tanning and other chemical treatment. The third stage applies retanning agents and dyes to the material to provide the physical strength and properties desired depending on the end product. This is known as Retanning. The fourth stage is used to apply finishing material to the surface or finish the surface without the application of any chemicals if so desired. This final stage is known as finishing.
Preparing hides begins by curing them with salt. Curing is employed to check putrifaction of the protein substance (Collagen) because of the chance of bacterial infection due to the time lag that might occur from procuring it to processing it. It removes the excess water from the hides and skins where water flows from inside because of difference in osmotic pressure. Thus the moisture content of hides and skins get greatly reduced.In wet-salting, the hides are heavily salted, then pressed into packs for about 30 days. In brine-curing the hides are agitated in a salt water bath for about 16 hours. Generally speaking, methods employed for curing greatly make the chance of bacterial growth unfavorable. Thus curing is also done by preserving the hides and skins at a very low temperature.
The hides are then soaked in clean water to remove the salt and mainly to bring back the moisture content to a desirable level so that the hide or skin can be treated with chemicals in an aqueous medium. This process is known as "Soaking" and sometimes a hydrating agent is also employed along with water in a very low percentage for hides and skins which have become very dry.
Liming Process of Hides & Skins:
After soaking,the soaked hides and skins are taken for the next operation where these are treated with milk of lime with or without the addition of sharpening agents like sulfide,cyanides,amines etc.The objective of this operation are mainly to:
1) Remove the hairs, nails and other keratinous matters
2) Remove some of the interfibrillary soluble proteins like mucins
3) Swell up and split up the fibers to the desired extent
4) Remove the natural grease and fats to some extent
5) Bring the collagen to a proper condition for satisfactory tannage.
The weakening of hair is dependent on the break down of the disulfide link of the amino acid called cystine, which is the characteristic of the keratin class of protein like hair and wools.The hydrogen atoms supplied by the sharpening agent reduce the cystine molecule to cystine and the covalent links are ruptured. The iso electric point of the collagen is also shifted to around 4.7, due to liming which is more towards an acidic tannage.
Unhairing Agents used during liming:
1) Sodium Sulphide 2)Sodium Hydroxide 3) Sodium Hydrosulfite 4) Arsenic Sulphide 5) Calcium Hydrosulfide 6) Dimethyl Amine 7) Sodium Sulphydrate
The majority of hair is then removed using a machine, with remaining hair being removed by hand using a dull knife, a process known as scudding. Depending on the end use of the leather, hides may be treated with enzymes to soften them in a process called "bating". But before bating,the pH of the collagen is brought down to a lower level so that enzymes might act on it. This process is known as "Deliming". Once bating is complete, the hides and skins are treated with a mixture of common salt and Sulphuric acid in case a mineral tanning to be done.This is done to bring down the pH of collagen to a very low level so as to facilitate the penetration of mineral tanning agent into the substance. This process is known as "Pickling". The common salt penetrates the substance twice as fast as the acid and checks the ill effect of sudden drop of pH.
Tanning can be performed with either vegetable or mineral methods. Before tanning, the skins are unhaired, degreased, desalted and soaked in water over a period of 6 hours to 2 days. To prevent damage of the skin by bacterial growth during the soaking period, biocides, such as pentachlorophenol, are used.
Vegetable tanning uses tannin (this is where the name tanning comes from). Tannin occurs naturally in bark. The primary barks used in modern times are chestnut, oak, tanoak, hemlock, quebracho, mangrove, wattle and myrobalan. Hides are stretched on frames and immersed for several weeks in vats of increasing concentrations of tannin. Vegetable tanned hide is flexible and is used for luggage and furniture.
Mineral tanning usually uses chromium in the form of basic chromium sulfate. It is employed after picking. Once the desired level of penetration of chrome into the substance is achieved,the pH of the material is raised again to facilitate the process. This is known as Basification. In the raw state chrome tanned skins are blue and therefore referred to as "wet blue". Chrome tanning is faster than vegetable tanning (less than a day for this part of the process) and produces a stretchable leather which is excellent for use in handbags and garments.
Depending on the finish desired, the hide may be waxed, rolled, lubricated, injected with oil, split, shaved and, of course, dyed. Suedes, nubucks, etc. are finished by raising the nap of the leather by rolling with a rough surface.
3. PATENT LEATHER
Patent leather is leather that has been given a high gloss, shiny finish. The original process was developed by Newark, New Jersey–based inventor Seth Boyden in 1818 with commercial manufacture beginning September 20, 1819. His process used a linseed oil–based lacquer coating. Modern patent leather usually has a plastic coating.
Patent leather is sometimes confused with poromeric imitation leathers such as Corfam and Clarino which are manmade materials with a similar glossy appearance.
Patent leather and poromerics are cleaned in a similar way. Dirt adhering to the coating can be removed with a damp cloth, using a mild soap if needed. Minor scratches and scuff marks in the coating itself can be removed using one of several special-purpose patent leather and poromeric cleaners on the market. With wear and tear, patent leather will eventually lose its glossy finish, but will still be smoother than most other types of leather, looking almost rubbery.
Patent leather and poromerics are used in applications where an eye-catching glossy appearance is the most important consideration. Examples include fashion items such as wallets and handbags, dance and uniform shoes, kinky boots and professional wrestling boots, and trench coats. In recent years patent leather has become a popular material for limited-edition sneakers made by companies such Nike, Bape, and Greedy Genius.
Sporting a high gloss finish, patent leather has long been established as leather that is considered uptown and formal.
The history of patent leather begins in the early 19th century and owes its invention to Seth Boyden of Newark, New Jersey. During the year 1818, Boyden began to investigate the possibility of creating a version of leather that was treated in such a way that the material retained its desirable qualities of protection and durability. At the same time, this new type of leather would also have an appearance that would be decidedly more dressy than work boots and similar leather goods.
Using a formula that was based on a series of treatments using layers of linseed oil based coats, the new shiny leather began commercial production on 20 September 1819. Boyden’s efforts resulted in the production of glossy leather that quickly caught on as a complement for formal dress.
Patent leather begins as a superior grade of fine grain leather that undergoes a process to achieve the glossy look. Originally, this was accomplished by applying layers of a linseed oil finish to the leather, gradually creating the sleek appearance. As time went on, the invention of plastics impacted the methods for producing patent leather.
Plastic finishes were able to produce effects similar to the application of several treatments with linseed oil, with the advantage of considerably less monetary investment on the part of the producer. Over time, the development of synthetic resins further simplified the process and cut production costs even further, making the mass production of patent leather possible.
Characterized by a glass-like finish that catches the light, the typical patent leather accessory is a solid black. In addition to the mirror like finish, patent leather is also virtually waterproof, while still retaining a very flexible texture. The visual aspects of patent leather have made it a sought after material for formal accessories. Most men’s footwear produced to be worn with tuxedos are patent leather shoes. Many formal types of heels for women are also produced using patent leather. Clutches and small handbags for women are also made using patent leather, as well as some formal wallets and cigarette cases.
Buckskin is the soft, pliable, porous preserved hide of an animal, usually deer, moose or elk, but potentially any animal's hide. Modern leather labeled "buckskin" may be made of sheepskin tanned with modern chromate tanning chemicals and dyed to resemble real buckskin. Leather is another product made from animal hide, but with a different chemical process to preserve the hide. Buckskin is preserved with a dressing of some kind of lubricant, physically manipulated to make it soft and pliable, and usually smoked with woodsmoke. Smoking gives buckskin its typical dark honey color, but is not required. Smoking prevents the tanned hide from becoming stiff if it gets wet, and deters insects from eating it as well. Unsmoked buckskin is lighter, even white, in color. Though it might be tempting to think that the name comes from buck, a male deer, the name buckskin comes from the alkali soaking process, called bucking. Clothing made of buckskin is referred to as buckskins.
There are many ways to make buckskin, but most can probably be lumped into two categories: "dry-scraping" and "wet-scraping". Before a hide can be tanned, any flesh remaining on the hide from the skinning process must be removed, usually with a scraper. Care must be taken when skinning, fleshing, and scraping a hide to prevent leaving any cuts or nicks in it which will be visible in the finished buckskin.
The dry-scrape method involves taking a wet deer hide and stretching it on a rack to dry flat. A scraping tool is then dragged perpendicular to the blade along the hair side, scraping off the epidermis and hair, including all the hair follicles. The flesh side should be scraped as well. When the entire hide is scraped, it is taken off the rack, rehydrated, and dressed.
The wet-scrape method involves scraping the wet hide on a smooth horizontal log, at stomach or sternum level. A steel blade or split leg bone can be used for a scraper. The hide is draped on the log, the person leans into it, holding the hide in place with their body and pushing the scraper away with both hands. The epidermis is scraped off, and the flesh side is scraped as well, to remove the membrane. If the hide is more than a day or two old, it should be bucked first. "Bucking" can be done in a solution of hardwood ashes in water, or simply lye in water. Bucking causes the grain layer (epidermis) to swell, making it more visible and easier to scrape off. If a small part is left on the skin it will poorly affect the finished product, so bucking is quite helpful. Bucking will also cause the hair to slip and fall off, if the hide is left in long enough. This is also valuable for some processes.
Once the hide has been scraped it must be dressed in a dressing solution. This can be made from the animals brain mixed into water, or from another emulsified fat. Egg yolks are an example of a commonly used, naturally-occurring emulsified fat. Another option is an oil and a soap mixed in water. Typically the wet hide is wrung out, then left in the dressing solution for 15 minutes or more, then wrung out and dressed again. Repeating this a third time ensures that the dressing reaches the middle of the hide.
The next step is stretching/drying. This is time sensitive, and has to be done from start to finish without stopping. The drying hide is continuously pulled and stretched in all directions, which lubricates the fibers of the hide with the oil of the dressing, and ensures that the fibers stay lubricated. This may be done on a rack with a stretching tool, or by hand. Often the hide is stretched against a steel cable or a rounded steel or wooden blade (with care not to cut the hide). This must be done until the hide is completely dry and no longer cool to the touch or else the finished buckskin will be stiff, and will have to be dressed and stretched over again.
The dry skin should now be totally supple and soft. If it gets wet at this stage it must be stretched again until dry, or it will revert to being a stiff piece of scraped rawhide. The water-soluble oils in the dressing will wash out with water. To waterproof the hide it must be smoked. When a hide is smoked, the non-water-soluble oil in the smoke bonds with the water-soluble oil in the dressing, making all of it non-water-soluble. Thus, a smoked hide can be washed, even with soap.
To smoke a buckskin it is folded in half and glued or sewn into a bag with an opening on one end. A pant leg or other cloth tube is attached to the opening of the buckskin bag. The smoking fire can either be in a woodstove or a hole in the earth. Either way a bed of coals is prepared, and the other end of the pant leg is roughly sealed over the opening of the smoker. The buckskin bag is suspended above the smoker, and sticks can be placed inside of it to prevent the sides of the bag from touching each other. A handful of dry, rotten ("punk") wood is thrown on the coals, and begins smoldering. Care is taken to prevent the cloth from catching fire, as the hide can be burned in seconds. Ideally most or all of the smoke is forced through the bucksin. All holes must be sealed or taped to force the smoke through. The hide is smoked until the smoke color penetrates through to the other side, then the hide is turned inside out and it is smoked again until it reaches a desired color.
The finished buckskin will shrink slightly after the first washing, so it should be washed or at least wet and dried before making clothing. Buckskin should be washed in cold water, and air dried. Hot water will destroy it. After drying it can be stretched or cabled for a short time to re-soften it. Nubuck is top-grain cattle rawhide 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. It is resistant to wear, and may be white or coloured. Nubuck was used by cowboys as it was light and comfortable.
Nubuck is similar to suede, but its texture is finer. It differs in that suede is created from the inner side of a hide, whereas nubuck is created from the outer side of a hide, giving it more strength and thickness along with a fine grain. It is generally more expensive than suede, and must be coloured or dyed heavily to cover up the sanding and stamping process. The word nubuck is probably derived from "New Buck".