Leather is an animal hide made chemically durable by tanning , the natural fiber structure of which is largely preserved. A distinction is made between the terms leather and fur ( fur ). Leather is mostly obtained from the layer of skin called the dermis . It consists of the smooth outer papillary layer and the underlying reticular layer , which provides mechanical strength. The papillary layer with its very fine fiber structure results in the grain side or “the grain ” for short on the finished leather . The coarse-fiber reticular layer is called the carcass or meat side, from which the split leather is obtained.
The body shell of larger animals such as cattle, horse, buffalo, donkey and that of pigs is referred to as leather as well as skin in the raw untanned state. The shell of smaller animals such as calves, goats and sheep is basically called fur. If the hair-forming epidermis or epidermis and hair are still preserved after tanning , it is fur or fur. After skinning, the hides and skins are usually flat. In the case of small animals, especially fur skins, the skin is often pulled off in the form of a tube.
For the technical description and quality assessment of leather, the density ( specific weight ), the tensile strength , the elasticity , the breaking strength of the grain (see flexometer ), the water and air permeability , the light resistance and the shrinkage are decisive. In addition to these physical values, chemical values such as fat content, shrinkage temperature when wet, tannin content, washability, acid content are assessed. For the chemical and physical parameters there are corresponding guide values for most types of leather.
Properties such as softness, structure and feel and appearance are difficult or impossible to measure. In practice, these properties are often just as important as the technical parameters when deciding whether and which leather to use.
Types of leather
Genuine nappa leather is a soft, chrome-tanned smooth leather from calf or sheep with full grains. It is colored through and the surface is finished, which means that the pores are closed by many wafer-thin layers and are therefore insensitive to dirt and moisture. The name nappa leather is used as a collective term for particularly supple smooth leather from all animal species.
A wide variety of leather items are made from beef leather. Nappa leather and ecru leather are made from the leather of calves , among other things . Other types of leather are only made from cowhide.
- Box calf
- From boxcalf , the leather obtained from calf, most of the high-quality men's shoes is manufactured, as well as bags and other leather goods with tender, tight fitting scars. It is divided into baby calf , box calf and fattening box according to the age and size of the animal . Boxcalf leather feels pliable and is still taut and very tear-resistant. The right side has an extremely fine grain structure, which gives it a pleasing pattern.
- Heifer leather
- According to a definition from 1900 (!) It is the leather of a non-grown cow ( heifer ). It is a step between calfskin and cowhide.
- Gold chrome
- Goldchrom is a chrome leather made from the hides of young cattle that is dyed yellow. It is mainly processed into sports balls.
- Mast box
- Mast box leather is a box calf leather made from the skins of fattening calves. It is used to make shoes.
- Beef box
- Cattle box made from cattle hides is the starting material for sturdier everyday footwear, as it has a solid structure and yet remains flexible. In terms of tanning and finishing, it corresponds to the box calf, but differs significantly in its fiber thickness in its area.
- Vachette leather
- Vachette leather or vachette was used for suitcases and handbags and was made famous by Louis Vuitton . The leather darkens and changes when it comes into contact with water and other liquids. It is made of large, split before tanning cattle hides, distinguish between strong greased and blackened Schmiervachetten , suitcase and Taschenvachetten and paint and Autovachetten .
The typical grain pattern is characterized by the crescent-shaped arrangement of the outer hair holes, which are distributed in a chain-like manner over the entire surface. As with the calf, nappa leather and ecrasé leather (cape goat) are made from the leather of young goats. In addition, there are types of leather that are only produced from goat or kid leather:
- is a chrome-tanned and dyed-through, extremely fine leather upper. The surface is smooth, soft, supple and has characteristic wrinkles. The best come from young goats (French: chevreau = kid). Older specimens have thicker and coarser scars. Originally, the term Chevreau leather was used to describe fine glacé leather of French origin. Chevreau is a goatskin that is tanned with a chrome double bath or combined. It is widely used on shoes and bags.
- Morocco or Morocco leather is a blackened morocco leather with fine scars. In bookbinding, on the other hand, Maroquin refers to a sumac-tanned, very durable goatskin from the skins of the African Cape goat , with a coarse-grained structure and particularly strong.
- Saffiano leather
- Real saffiano leather is made from the skins of East Indian goats and tanned with sumac ; a distinguishing feature is the typical "crunch". The name is derived from the city of Safi in Morocco . Saffian is used, for example, for book covers because of its strong, tough and very durable material.
- An imitation of the Chevrea leather by sheep leather, here the classic hair hole arrangement of the goat leather is missing.
- an imitation of goat's saffiano leather by sheepskin
- Skivers are very thin gaps in the grain of sheepskin . Some of them arise in the production of sheep or lamb velor and often only consist of the papillary layer. As a result, they usually have very poor mechanical properties and are laminated onto carrier materials during processing. They are used as lining leather for small leather goods.
- Wash leather
- Wash leather is usually a lamb leather that is sanded very thinly. It can be washed with almost no loss of quality and retains its softness when it repeatedly becomes wet and dries out.
- Pig leather does not have the same quality as that of horse, goat or cattle. It is often used for low-priced street shoes. However, porcelain leather is quite hard-wearing and dimensionally stable, which makes it perfectly suitable for processing in durable footwear. The leather can be recognized by its characteristic grain pattern caused by the papillae.
- Peccary is a South American wild boar that occurs in the tropical rainforests of Amazonia and provides the high-quality peccary leather. Softness, toughness and a velvety feel characterize the rare leather.
- The hides of the peccaries hunted in the rainforest are collected, dry-preserved and brought to the tanneries by traders. In order to maintain the population of the animals, regular counts are carried out, based on which the trade is controlled. The very expensive leather is mainly used for high-quality gloves (car gloves), but also for light shoes, small leather goods or luxury clothing. Peccary leather goods have good durability and if the leather gets wet, it can develop dark spots.
Horse leather, cordovan
- Cordovan denotes the rear portion of Ross skins , the so-called shells or butts ( croups contains). The name is derived from the Spanish city of Cordoba, which once specialized in the production of goatskin under the same name. Its leather thickness is between 1.6 and 1.8 millimeters, but is not inferior to the suppleness of box calf leather. Cordovan is to be found in the upper leather price segment because of its low availability, on the one hand the supply of raw materials is steadily declining and on the other hand the leather obtained from the rear of a horse is quite small.
Reptile leather has a characteristic grain pattern with scales, is very dimensionally stable and is mainly used for luxury objects.
- Crocodile skin
- The skin of young, bred crocodiles is primarily used to produce real crocodile leather. Adult specimens have scales that are too large and strong, which break easily when processed. In the case of imitations, the typical grain pattern is embossed on smooth leather.
- Lizard leather
Fish leather is made from the skin of fish. Use finds particular eel leather and leather Dorscheen , stingrays TYPES (z. B. manta rays ), sharks , etc. It is used because of its interesting dermis mainly for shoes and bags.
Ostrich leather has a characteristic goosebump-like grain pattern with large feather bellows. It is particularly durable and can be recognized by the typical nodules on the back. In the case of imitations , the typical grain pattern is embossed on smooth leather.
Kelly bag made of gray-green ostrich leather
The chemical composition of the leather depends on the respective manufacturing process. The proportion of the actual leather substance can fluctuate. A vegetable-tanned leather has a higher tannin content and a skin substance of 38 to 46 percent, while a chrome-tanned leather can have up to 72 percent skin substance. Alum and chamois tanned leather are in between. The water content of the leather is also assessed. Leather is hygroscopic and therefore the water content is always dependent on the surrounding air humidity . In the case of vegetable-tanned leather, it is around 14 percent, and in the case of mineral-tanned leather, it is slightly higher by 18 percent. If the fat content in the leather increases, the water content decreases. The amount of water in the leather is one of the factors that determine tear resistance, grip, stance, weight and elasticity. The fat content depends, among other things, on which animal the skin comes from. Normally the natural fat content of the skin is around one percent; an exception is sheepskin , which has a natural fat content of up to twelve percent. A fat content of up to 50 percent can be achieved during the production process. The fat content, like the water content, influences the properties of the leather: tear resistance, elasticity, water absorption capacity.
The amount of bound tannin is also important . This is understood to mean tanning agent bound to the proteins of the skin in relation to the skin substance. Vegetable-tanned leather contains 24 to 32 percent, mineral-tanned four to six percent and fat-tanned leather twelve to 18 percent bound tannin. In addition, the leather contains various minerals that come from the manufacturing process (liming, tanning ). The content of vegetable-tanned leather is normally less than two percent and that of mineral-tanned leather between seven and nine percent.
Prehistory and Roman Empire
The 5300-year-old glacier mummy Ötzi offers a unique insight into the diversity of Stone Age leather processing . Their shoes, outerwear and hats were made of different leathers that were tanned by fat and smoke. A leather shoe from Armenia discovered in 2008 is a little older . It was discovered in the Areni I cave ( Vajoz Dzor province ) in layers of the Copper Age and dating from 3630 to 3380 BC with radiocarbon dates . Dated.
Long before the turn of the century, leather items were in use in Egypt , Mesopotamia, and the Israelites . The vegetable tanning was already in the 4th millennium BC. Known in ancient Egypt . On the sarcophagus of Ti, a wealthy Egyptian who lived around 2850 BC. BC and 2700 BC Died, scenes with tanners can be seen.
During the Roman Empire, a lot of leather was used to make legionnaires' equipment. The production was regulated mainly in Rome by a guild of leather and hide sellers from Ostia . The leather trade was one of the reasons for the Punic Wars , among others ; Carthage was an intermediate trading place between the markets of North Africa and those of the Mediterranean and thus had a monopoly on the leather trade in Europe and the Mediterranean .
From the 3rd century on, the leather trade was under Roman supervision. South of France and Spain were probably the production centers of that time. This is confirmed above all by finds in Botonita ( Zaragoza ); there, large amounts of lime , sulfur and other chemical products were found that were probably used for tanning. In the excavations in Contrebia Belaisca , evidence of the existence of leather production from the period between the 1st and 3rd centuries BC was also found. Discovered.
Middle Ages to Baroque
After the fall of the Roman Empire in 747, Charlemagne took over the legislation regarding leather production and its trade and at the same time imposed a tax on some products. During this time leather was processed relatively roughly. It mostly came from a nearby catchment area, although leather was also imported in individual cases.
In the Middle Ages , the manufacturing process in the Near East and North Africa was much more advanced than in Europe, both in terms of quantity and quality. It was not until 1749 that the first saffiano leather factory was built in Alsace . Leather was often imported from Siberia for the fashion of the time .
For a long time, the production of individual types of leather was reserved for individual regions or cities in Germany.
- Sole leather in old pit tanning in the Rhineland , especially in Trier , Malmedy (now Belgium)
- Fast-tanned sole leather in Northern Germany, especially in Hamburg
- Horse leather in Holstein
- Patent leather, especially patent calf leather in Worms and Mainz
- Patent leather for car tops in Mülheim an der Ruhr
- fine calf leather in Barr in Alsace
- Kipsuppers in Backnang
- colored leather in Offenbach am Main , where the leather goods fair still takes place, and in the Taunus
- Glacé leather in Berlin , Magdeburg , Altenburg and Munich
The history of leather goods production is documented in the German Leather Museum in Offenbach.
Leather is often used for particularly stressed clothing. It can still be found, for example, in cowboys , who probably prefer it because of its high tear strength and resistance to wind and weather. The first pilot and motorcyclist helmets were made of leather. More recently, heavy metal groups have also been associated with leather clothing .
In the 19th century there are various references to leather in literature where its use plays a role in relation to the human imagination, including sexual orientations. So has Leopold von Sacher-Masoch , from whose surname the masochism derives much from the erotic side felt attracted to the leather. He shows this in his novels Venus in Fur and False Ermine . In the BDSM field , the use of leather clothing and accessories is also widespread.
Leather has been used for seat covers and vehicle interiors since the early days of automotive engineering . Partial or full leather upholstery is usually optional equipment that is subject to a surcharge. Due to the high stress, such as cold, heat, moisture and solar radiation, there are special requirements here, in particular with regard to elasticity, abrasion resistance, light resistance and low flammability.
Any animal hide can be used for the production of leather. The starting material is often decisive for the quality. The vast majority of leather comes from cattle , calves , sheep , goats and pigs ; they are a by-product of the food industry . Cattle hides in particular can be used for a wide variety of uses.
There is also leather made from the hides of exotic animals and - rarely - of other origin. The shoe , handbag production and other fashion industries in particular have discovered exotic sources. These include crocodiles , game ( deer , deer , elk ), bison , buffalo , kangaroo , ostrich , fish ( eel skin ) and snakes . Crocodile skin and snake skins in particular were very fashionable for a while, which almost led to extinction in some species . In the 1970s, ostriches were mainly bred, the meat and leather of which could be used in a variety of ways. Ostrich leather is considered to be very fine and very durable, it is still processed into fashionable articles. Kangaroo leather is often used for motorcycle gloves, for which it is more suitable than cow or cow leather due to its strength and elasticity.
The skin of dogs and cats was made into leather. Dog Leather was in the Middle Ages to the modern era in the field of printing and other printing techniques used, in which the order of printing ink on the printing block with a leather carried tampon. Since the dog has a pore-free leather - its skin is not penetrated by sweat glands - dog leather was mainly used for it. At the beginning of the 20th century it was still very popular for certain items such as gloves.
Some finds from the 11th century show that cat fur was worn by the Vikings and traded in Europe in the Middle Ages. At that time and about a hundred years ago, French and English furriers in particular valued cat leather as a particularly supple material for gloves. There are even a few examples of the use of human skin for book covers ( anthropodermic bibliopegy ). Dog and cat fur are now subject to a trade ban in Europe.
In the tannery , perishable hides that are exposed to natural degradation processes are turned into a more durable product. The skins are first preserved in salt or by drying. The skin is prepared for the actual tanning in various processes in the water workshop such as soaking, dehairing (liming) and flesh removal (mechanical removal of the subcutaneous tissue), decalcifying and enzymatic staining. The desired leather properties are already significantly influenced in these work steps. During the actual tanning process, the previously raw hide is converted into leather. Various raw materials can be used in the tannery.
In vegetable tanning (vegetable tanning, tannery), tannins are used in oak or spruce bark , extracts from quebracho , chestnut or oak , mimosa , sumac and other wood or bark tanning agents (" Gerberlohe "). In mineral tanning, chromium salts, aluminum salts, alum (white tanning) and zirconium salts are used. In addition to the mineral and vegetable tanning agents, synthetically produced tanning agents (syntans), aldehydes (glutaraldehyde, formaldehyde) and fatty tanning agents (Trane) are used for tanning. While tanning used to take place mainly in brick pits with little movement, these processes are carried out in rotating barrels made of wood, stainless steel or plastic. The structure is similar to that of a washing machine drum, but with a capacity of several cubic meters.
The frequent industrial chromium salt tanning produces toxic waste products and carcinogenic residues also accumulate in the leather itself. Research is being carried out on inexpensive herbal alternatives. In the meantime, a tanning agent based on olive leaves and patented in Germany is now being used on a small scale.
After tanning, the skin has a rough and a smoother side. The rough side is called the meat side (carrion side), as it was originally facing the meat. The smooth one is referred to as the grain and has the respective surface structure typical of the species. This grain side can be adapted to its intended use in various processes. Chemical and mechanical processes come into question.
The Eskimos made their leather in a special way. The skins were tumbled and then chewed with the teeth until they were completely supple and soft.
All tanning work according to the so-called golden tanner's rule , which says: start / tan in small pieces or with little tendency of a tanning agent to bind to the skin substance (collagen). To a large extent or with a high tendency to bind a tanning agent to the skin substance to the end / eradicate. This is done in order to avoid a blockage of the penetration routes of the active ingredients and to allow the spread of subsequent tannins.
Wet blue / wet white
As wet blue a moist chrome-tanned leather during processing is called. It is already tanned in this condition; Neutralization, retanning, dyeing, fatliquoring and dressing are still missing. The blue-green color is produced by the chrome. Leather tanned with synthetic materials is called wet white in this phase .
Crust / bark
- Crust or bark leather is called dried wet blue or wet white leather that has not yet received any color or finishing.
Thickness of the leather
Leather can be split before and after tanning (split leather). The scar gap is generally the more valuable part of the skin. The meat gap has two rough sides and is processed into suede or used with a coating (dressing, dressing agent ) as a substitute for grain leather. Leather that is not split is also called full leather . The exact thickness regulation takes place after tanning by "folding". Folding shavings are removed from the leather by rotating knife rollers.
Retanning, dyeing, fatliquoring
Basic leather properties such as softness or fullness arise through the work of the water workshop and through tanning. The aftertreatment with tanning agents (retanning), dyes and fatliquors defines the properties for the specific purpose of the finished leather. In the case of mineral tanning in particular, these work steps determine the later leather properties, above all softness, elasticity, fullness, water absorption and dyeability.
The natural color of the leather depends on the tanning agent. In the tannery yellowish and reddish-brownish tones are obtained, in the sumac tanning yellowish, greenish and brownish, in the white tanning white, in the chrome tanning blue-green to gray and with fatty tannins yellowish leather. Leather is also often dyed. The dyeing was already known to the Egyptians, where the leather was dyed costly with purple snails . Until around 1860 the dyer was dependent on natural raw materials. Here played dyewoods , root extracts and saps a big role. Substances from animals and lichen were also suitable for dyeing leather. Many different coloring substances are used, for example from the groups of azo dyes , triphenylmethane dyes , aniline dyes or sulfine dyes . According to their type of coloring, a distinction is made between acidic, substantive and basic development dyes.
The coloring takes place mainly in the liquor in fulling drums, but can also be done by spraying, brushing or on roller application machines. Dyed leather is either dyed through or surface-dyed. The dyes used form a chemical bond with the leather and do not impair the natural surface character. If these leathers are given little or no coating (dry finishing), they are sometimes referred to as "pure aniline leather". Completely aniline-dyed leather has the same color on the top and bottom, so scratches or wear are less noticeable. Leather with a thicker coating is referred to as "semi-aniline" or, if the coating is mixed with opaque pigments, as covered leather. This covering makes the natural grain disappear and is also used to conceal previous injuries to the animal or insufficient further processing.
The surface treatment of the grain side can give leather certain effects. It can be glossy or matte. The resistance of the surface can also be significantly improved. The treatment is mainly carried out with environmentally friendly, water-thinnable binders, pigments and additives. The application takes place in several layers by spraying, pouring or using roller application machines (roller coaters). The layers are smoothed by ironing, polishing or buffing and firmly anchored to the leather. The leather can be given an artificial surface structure by crinkling , embossing , perforating or shagreening . Patent leather, in which an oil varnish , a cold varnish or a foil varnish is applied to the leather surface, is one of the finishes of the leather surface. If the flesh side is sanded and used as a visible surface, it is suede . With nubuck leather, the grain side is sanded with fine sandpaper.
Leather in its many-layered areas of application can be decorated and adorned in a variety of ways after processing. Leather can be painted and re- colored . With hot stamps, a pattern can be applied in blind printing ( gaufrage ) or in gold or other colors. The Egyptians used decorative techniques such as cutting, scoring, underlaying, braiding , cutting, punching , embroidery and other applications. In the bookbinding the technique of is leather-section used. Leather can be shaped in relief by pressing and pressure.
Leather and fur are among the oldest materials used by mankind, along with wood , stone and wool . In addition to shoes and leather clothing, products made of leather are referred to as leather goods or portfolios. Throughout history, leather has also been used for weapons and implements. Various wooden objects were covered with leather, such as chests and smaller boxes . Dice cups were mostly made of leather, as were the first buckets . The North American Indians used leather for clothing, for straps of all kinds or as a tent ( tipi ), but also as writing material (see below).
Parchment is a processed but untanned animal skin that has been dried under tension and has been used as writing material since ancient times. It is thus a forerunner of paper. Long before the invention of parchment, leather was used as writing material in the form of scrolls . North American Indian tribes used tanned buffalo or deer skins as writing material for ideographic picture writing , such as the Kekinowin of the Ojibwa Indians , who belong to the large Algonquin language family . In the bookbinding business , simple leather, in addition to the animal hide refined to parchment, served as material for bindings and binding design from the beginning . The bookbinder also uses it to cover boxes, slipcases , cases and cases . Leather was also used as wallpaper (historically also gold leather wallpaper ) for wall design.
Leather is traded according to the area of the fur . The usual unit of measurement is square meters, the unit square feet is still used. A square foot of leather is 929 square centimeters.
Shoes, clothing and accessories
Most of the leather produced worldwide is used for shoes. Different types of leather with different properties are required for the production of a shoe, depending on the type of shoe, very solid, wear-resistant sole leather, perspiration-resistant insole leather, skin-friendly lining leather, firm but embossable frame leather and leather for the shoe upper, which is referred to as upper leather and depending on Shoe type has different properties. Typical types of leather for upper leather are: calf box (box calf), cattle box, chevraux (goat leather), hunting (suede made from cowhide or calf), waterproof, shoe and boot nappa. In some cases (mainly for shoes in the luxury segment) exotic types of leather are also used for the upper material, for example reptile leather for western boots .
In the manufacture of clothing , leather is mainly used in three areas: firstly in the sector of fashion and everyday clothing, there is also the area of protective , work and functional clothing made of leather and finally clothing that is used in the BDSM and fetish scenes ( see for example leather scene ) is used. Leather jackets in particular have established themselves in the field of clothing fashion and everyday clothing . But lederhosen have also become part of everyday clothing, for a while in the 1950s they were given the status of rebellious youth clothing. Especially in Bavaria and Austria , the specific lederhosen are an essential part of traditional costumes . Lederhosen in jeans cut or in the cut of classic suit trousers were in fashion in the 1980s. Lederhosen in jeans cuts, some with laces, are common in the biker and heavy metal scene. In the area of functional and work clothing, jackets such as flight jackets and motorcycle clothing , but also aprons and helmets, should be mentioned. Almost every piece of clothing can also be made from leather ( jackets , pants , coats , gloves or hats ).
Widespread accessories of leather can be: bags , handbags, wallets (see also Money cat ) or wallets , suitcases , boxes, jewelry boxes , cases , belts and hats. Leather is offered in the form of leather cords as jewelry chains with pendants, as leather bangles or as hair accessories .
Other leather products
In the production of furniture and in interior design or furnishing , leather is mainly used as a cover for seating and upholstered furniture , such as leather sofas and leather armchairs . Sometimes - but less often - as cladding or covering walls or other furniture (cupboards, desks, etc.)
Similarly, the material can be found in the interior design of cars and other vehicles. Here again primarily leather seats, but also steering wheel and cockpit cladding as well as the cladding of other interior surfaces in cars, trains and other means of transport with closed passenger compartments can be mentioned. The use and retrofitting with leather as interior material or for leather seats is considered a high-quality equipment feature (see: Vehicle tuning ). In the case of a bicycle , the seat of the saddle can be covered with leather or made entirely of leather.
In the sports sector , leather is mainly used for covers for balls ( soccer , handball , medicine ball ) or sports equipment ( bucks ), and also for sports equipment such as punching bags , boxing gloves , knee pads and sports clothing and sports shoes. “The leather” is used almost as a substitute for the expression “ball”.
Leather was used for transmission belts , drive belts and the like very early on . The bellows were also partly made of leather. Before plastics were used , leather was used to insulate electrical cables. Leather is also used as a seal , as cleaning, washing and filtering leather. A historical example of the use of leather straps is the bandalier (upper body belt ).
In musical instrument making, leather is used in special cases. The organ builder uses leather as a seal for both fixed and moving parts, while leather is used in the strike mechanisms in piano construction. The keys of wind instruments were earlier and some are still made of leather.
Leather is the predominant component of saddles and harnesses for horses and oxen in equestrian sports and agriculture . But leather straps are not only used for workhorses , but also for dog collars or dog leashes . Whips are mostly made from leather cords.
The Roman soldiers sometimes wore a kind of padded leather vest under the armor or chain mail, which was decorated with leather strips on the shoulders and lower edge. The military boots of the Roman army were used for covers that were pulled over the shields during the march to protect them from moisture and damage. Leather was used for the arrow quiver of archers needed for guns - holster or sheaths for knives.
In professions that cut with blades, strong strips of smooth cowhide leather were or are sometimes still used to smooth the edge, either as a handheld tool ( barber, hairdresser ) or attached to the worktop (furrier).
There are numerous leather-processing craft trades, such as the bag maker or Austrian bag maker, fine bag maker , tanner, punch , bookbinder, furrier, belt maker , saddler , shoemaker or shoemaker . In the Middle Ages, leather professions were organized in guilds , such as leather workers, as well as white and red tanners and Corduan makers. Other more historical job titles are: Beutler , bag maker and parchment maker. A relatively new profession that also deals with leather is the restorer , especially the book restorer and the restorer of archaeological finds .
- Alum-untanned leather was tanned with aluminum salts ( white tanning ).
- Old pit tanning is carried out for the production of high-quality sole leather. It is a pure vegetable tanning process and only ground tanning agents (bark, leaves, woods and fruits) and no tanning extracts may be used. The tanning time is up to twelve months.
- Chrome leather was invented in 1858 and is tanned with trivalent chrome salts.
- Vegetable tanned leather . This leather was tanned using vegetable tanning agents (e.g. bark). (low shrinkage temperature).
- Russia leather is of Russian origin. The manufacturing technique is described with jufte (“pair”). For the tanning, two hides of the Siberian steppe cattle were always stapled together, tanned with willow bark, impregnated with birch tar oil and dyed reddish. It's pliable, very durable, and well waterproof (the forerunner of Waterproof).
- Rhubarb leather by tanning with extracts of the rhubarb root.
- Chamois leather is a type of leather that is onlytannedusing fat (originally whale oil ). The hides of chamois, roe deer, deer, reindeer , goats , sheep, calves and cattle were usedas raw material. It is mainly used as wash leather and chamois leather.
- Shrink leather shows a strongly structured grain layer. The structure is created by a special tanning process and is much more durable than with embossed leather. It is used for shoes, bags and suitcases.
Used part of the rawhide
- Split leather is obtained by splitting. A distinction is made between the grain gap and the flesh gap. The former consists of papillary and reticular layers and has a smooth surface. The latter consists only of a reticular layer. The smooth surface of meat cracks is often reproduced by coatings with foils or polymers.
- Full leathers are the upper parts of the hide on the hair side, which have been brought to the required thickness by processing from the flesh side.
- The term raw hide is a largely untreated, depilated skin on the market that is used for special purposes such as bridles, drums, bow weapons or dog bones.
- Hide leather is obtained from the core area of the raw hide. The skin is thickest in the areas close to the spine. When it comes to strength, bend leather is preferred.
According to the origin of the skin
After surface treatment
- Aniline leather has a thin finishing layer, the natural structure of the leather can be seen here, as it is only a color correction with liquid substances. In the past, harmful aniline dyes were used, which can instead be replaced by liquid metal complex dyes with very similar properties.
- Chagrin is a pressed grain leather. To produce a press scar, the original scar is ground off and a new scar is pressed on ("shagrin"). It used to be made from the leather of the horse's or donkey's back, but it can also be made from shark or ray skin. It is mostly a chrome-tanned cowhide or mast calf leather with press grains and finishing with an opaque color.
- Color leather
- Chicken leather does not come from chickens, but describes a fine sheep or goat leather.
- Crumple lacquer is a leather that is covered with a water-insoluble lacquer layer. It is mostly split leather, which is soft and flexible.
- Patent leather is leather covered with a thick layer of lacquer and therefore no longer has any natural characteristics. This type of lacquer clothing is firm and practically without stretching, waterproof and easy to clean.
- "Cool leather". Specially tanned leather that, unlike conventional leather, does not heat up as much in the sun because color pigments reflect the sunlight. It is mostly known on the market under the name TFL Cool System®.
- Nubuck leather is created when the surface of cowhide or calf leather is sanded to create a fine, velvety roughened structure. The scar is pure and flawless. The pelts are chrome-tanned and deeply colored. By brushing your hand over the leather, you get a line like velvet. Nubuck is a typical type of suede.
- Suede is a collective term for leather types with a roughened surface that are sanded on the flesh or grain side. A distinction is made between: grain-side processed leather such as nubuck, flesh-side processed leather such as goat suede, grain-side and flesh-side processed leather such as pigskin and suede as well as split leather.
- Sanding box is a cowhide whose faulty grains are sanded and in which artificial grains are reproduced through a relatively thick finish in order to obtain a very high level of smoothness. These leathers are almost always made with a grain impregnation, as the dressing should lie very tightly and should not lift off or form small creases when the leather is bent. Grain impregnation means that binding agents are incorporated into the leather surface, which greatly reduce the mobility of the leather fibers. Only then is the finish applied. Grinding box is mainly used for shoes and bags.
- Suede has a rough, velvety surface. It is formed by the reticular layer, which is ground more or less finely. Suede is mainly made from pig or cowhide , sheep, goat or calf skin. If meat slits from cattle or calves are used, it is split velor.
- Cowhide leather with chrome tanning is usually waterproof and has been given a special treatment ("hydrophobizing") to show low water absorption and good water resistance. They are mainly used for heavy shoes (mountain boots, military shoes, work shoes) or motorcycle clothing.
According to intended use
- Saddlery and bag maker leather
- Harness leather. Blackened or natural, more heavily greased bare leather.
- Fine leather. Collective term for the types of leather processed in the fine bag making.
- Shoe lower and upper leather
- Sole leather. Thick, not pliable leather of vegetable tanning, mostly cowhide
- Furniture leather and car leather
- Clothing and glove leather
- Bookbinding leather
- Lining leather
- Pump leather
- Technical leather
For the following types of leather, the focus is on their use.
- Smooth leather is a vegetable-tanned, lightly greased natural or dyed cowhide with a uniform appearance in fiber structure and thickness for saddles, bags and riding gear.
- Glacé leather usually consists of lamb, kid or calf leather. It is very soft and washable thanks to a special treatment. Because of its softness and tensile strength, it is particularly suitable for gloves.
- Mochaleder or Mochetto are polished on the grain side cloth-like trimmed lamb and Zickelfelle or calfskin. They are among the most expensive, softest and most durable types of glove leather.
- Oasis goat is a bookbinder's leather made from the skins of the Sudan goat in Central Africa .
- Vacheleder is a flexible sole leather that is made from cow hides. Tannins are used in production, which tend to result in soft leather. Vacheleder is also lightly greased. A distinction is made between Schnittervache (strong sole leather, which is produced according to the modern tanning process), Nagelvache (a somewhat stiffer sole leather), Sewing vache (flexible and somewhat softer sole leather) and Flexibelvache (very soft sole leather, processing by gluing).
- Ecrasé leather is made from cape goat or calf skin. After its coloration, it is characterized by small, light “veins”.
- Nappa leather is very soft and flexible and is used for purses and other leather goods. It is made from lamb, kid or calf leather. Nappa leather still has the natural surface on which the hair once sat. This surface is not sanded.
- Soft nappa leather as nappa leather very soft, but shines because of its treatment less.
- Suede is still occasionally used as a term for roughened leather, more correct and now more common is suede . Actual “game” leather comes from chamois, roe deer, deer, East Indian goats, antelopes , gazelles , elk or reindeer. It is tanned mainly chamois, the grain is completely shed off.
Like any other material, leather can be damaged by constant use. This includes damage such as tears, abrasion, stains, water marks, etc. Often there are cracks in the surface of leather, which may have been triggered by excessive dryness or too high a fat content in the leather. Apart from daily wear and tear, shoes can also be damaged by sweat . To avoid this, leather that is more sweat-resistant is used. Weather ( rain , snow , sun and wind ) can in the long term have a damaging effect on items and clothing made of leather. Regular leather care prevents damage.
The tanned leather can become acidic over time . The resulting acid degrades the leather. This process is favored by sulfur-containing substances in the air, such as those created by gas lighting . In the past, this was often the case in libraries , so this phenomenon was given its own name: in English it is referred to as red rot , in German also as red decay . The leather is completely destroyed by the binding of moisture and sulfur dioxide through the formation of sulphurous acid and the surface disintegrates into powder. With simultaneous low humidity (less than 40 percent), this process results in dry, irreversible damage to the fiber structure of the leather over a longer period of time. Various home remedies are recommended, but it is better to consult a knowledgeable restorer. If the acids from the tanning process are not sufficiently neutralized , the collagen in the leather can hydrolyze , which can cause the skin to break down after a few years. In addition, residues of biological fats can become rancid and lead to fat eating in the long term . In addition, various types of bacon beetles ( common fur beetles , brown fur beetles ) can cause damage to their food. If stored too moist, various molds and bacteria can lead to decomposition .
Leather preparation / leather restoration
Leather can be restored; there are different types of damage. If leather has become brittle with age or if parts of the leather have even been lost, extensive repairs can also be made. There are various auxiliary materials available to remove damage. A so-called liquid leather is applied with a spatula if the surface is damaged. The surface structure can also be reconstructed by previously molding at another location and transferring it to the repair surface.
In order to make leather more durable, stain-resistant and permanently water-repellent, an opaque color layer based on pigments and binders is applied to smooth leather that has been pre-dyed with aniline dyes. This color layer is also called head coloring, dressing or pigmentation. Smooth motorcycle leather, but also many casual jackets, shoes, car and furniture leather and bags made of smooth leather have this additional layer of color. The top coat , a type of clear lacquer, is also applied to this layer . The top coat protects the binder color from abrasion and discoloration and determines the degree of gloss and feel. As additives, crosslinkers ensure improved fastness properties.
Leather should have a water content of 14 to 18 percent. As the fat content increases, the water content of the leather decreases. Due to the water content of the leather, tear resistance , grip, stance, weight and elasticity are greatly changed. The natural fat content of the skin is 1 percent. Only sheepskins have a natural fat content of up to twelve percent. Like the water content, the fat content also has a strong influence on the properties of the finished leather, such as elasticity, tear resistance and water absorption capacity. Leather care products must therefore be handled carefully with valuable objects - in case of doubt, a specialist (leather restorer) should be consulted.
Shoes are subject to comparatively high stresses from external influences such as dirt (= abrasive friction), moisture (= risk of washing out fat and colorants), friction and impacts on the surface (= mechanical damage), which cannot be avoided in everyday use. In addition, the leather is constantly stressed by foot sweat, tension, pressure and flexing movements. Often there are also chemical influences from the stocking materials or detergent residues. That is why leather shoes require regular maintenance.
The care of smooth leather uppers consists of applying a thin layer of shoe polish after thoroughly cleaning the surface and then polishing it. This creates a largely closed protective film, which, especially when using a hard wax cream (can cream), optimally protects the upper leather, shines and makes it difficult to get new soiling. In the case of very heavily used shoe uppers (work boots, mountain boots, etc.), the protection provided by hard wax cream, which is sufficient for chrome-tanned uppers of normal everyday shoes, is not satisfactory. There are therefore special care products such as fat waxes, leather fats and others.
Shoes made of suede (suede and nubuck) have very open-pored shafts and therefore require regular thorough brushing in order to remove the dust that has penetrated. Occasional impregnation with impregnation liquids or sprays prevents premature new soiling and ensures a certain degree of a water-repellent effect. Leather soles can be cared for with special leather sole oils. This reduces abrasion and creates additional water repellency.
If soaked shoes are dried more quickly using heat (radiation or warm air), there is a risk of irreversible chemical conversion of the leather fiber. As a result, the leather hardens, becomes brittle and tears or breaks easily. This applies to both leather uppers (particularly at risk: vegetable-tanned leather) and leather soles. For this reason, soaked shoes are only stuffed with newspaper, which absorbs the moisture and is regularly replaced. It is best to have air around the shoe on all sides (if leather soles are present, even by hanging it on a clothesline). To avoid losing the fit, a suitable shoe tree is inserted into the slightly damp shoe towards the end of the drying phase.
Clothing and accessories
The cleaning of clothing belongs in the hands of a professional, where it is usually carried out with organic solvents . Nappa leather is better protected against dirt, water and dust because it has a more closed surface.
Glacé leather gloves can be cleaned with benzine . Gloves made of nappa leather, pigskin and suede can be washed with soft detergents or special detergents . They are then washed with their clothes on, after which they are inflated and slowly dried. The almost dry glove regains its original shape by smoothing it out, and by crumpling and stretching it can become as soft as before.
Leather furniture can be cleaned with a soft, possibly slightly damp cloth. Corresponding leather cleaners are available for heavier soiling and can be used without hesitation on pigmented types of leather. However, the use of leather care products is problematic for some types of leather such as nubuck leather. In any case, you should consult a specialist who specializes in cleaning and restoration using original tannery products.
Valuable leather objects should be carefully stored. This includes protection from high-energy solar radiation, dust, dirt and moisture, for small leather goods, for example in a cloth bag. For museums, an average temperature that is as constant as possible and a relative humidity of 45 to 55 percent are recommended for preserving leather . A higher level of humidity promotes the formation of mold; if the level of humidity is too low, the leather is brittle. Adequate air exchange should be ensured during storage.
If the leather object is already damaged, brittle, torn, rubbed off, warped or covered with mold, a trained restorer should be consulted.
Alternatives to leather
Due to the complex and therefore expensive production, imitations of leather, so-called artificial leather , are often used instead of real leather . Artificial leather can replace or even surpass the positive properties of real leather in some areas (in terms of tear resistance - drive belts, abrasion - shoe soles, water impermeability - shoes, protective clothing, visual impression). If, however, many of the properties are required at the same time, leather is still superior (in terms of mechanical strength and breathability, toughness, haptics , moisture absorption, wearing behavior in clothing). In addition, leather in the broader sense is a renewable raw material that is a by-product of food production in almost all cultures.
Recently, products made from bonded leather have increasingly appeared. These are materials made from the smallest leather particles, which are put back together with binding agents.
As with almost every type of animal use, animal ethics and ecological aspects are criticized in leather production . Leather is usually a by-product of meat production. However, there are animal species that are primarily hunted or bred for their skin, such as crocodiles, lizards and snakes.
The tanning is not harmless. Chrome tanning, which is less complex and less expensive than, for example, vegetable tanning, is widespread. For this purpose, chromium (III) and aluminum salts are used, as well as a number of other chemicals which, if not disposed of properly, are harmful to the environment or toxic. Due to the widespread chrome tanning process, more and more residues of highly toxic chrome (VI) compounds were measured in leather products , which can be carcinogenic or even mutagenic if they come into contact with the body. This problem can be prevented by careful process management during chrome tanning. Many types of leather can also be produced in the appropriate quality without chromium salts.
- Calw (Northern Black Forest): tannery museum ( white tannery courtship )
- Doberlug-Kirchhain (Elbe-Elster district, Brandenburg): Doberlug-Kirchhain White Tanner Museum
- Enger (North Rhine-Westphalia, Herford district): Enger tannery museum
- Mülheim an der Ruhr: Leather and Gerber Museum
- Offenbach am Main: German Leather Museum
- Ohrdruf (Thuringia): Old tannery (Ohrdruf)
- Weida (Thuringia): Tannery in Weida (technical exhibition monument)
- Eisenerz (Styria): Tannery Museum Gerberei Salzer
- Bosa (Sardinia): Museo delle conce (Leather and Tannery Museum)
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- Josephine Barbe: Leather - History, Techniques, Projects , Bern 2007, p. 42.
- Josephine Barbe: Leather - History, Techniques, Projects , Bern 2007, p. 40.
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- K. Fuchs, M. Fuchs, L. Derichs: Fascination Leather - Everyday and Exotic Under the Magnifying Glass . 2008, p. 31.
- Josephine Barbe: Leather History, Techniques, Projects , Bern 2007, p. 44.
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- Discovered the oldest leather shoe in the world (Spektrum direkt, accessed on June 10, 2010) .
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- Brand one : That doesn't go on a cow skin. Quotes: “The chromium sulfate used in tanning can turn into the harmful heavy metal chromium VI. [... In olive leaves ...] there are bitter substances that protect the tree against predators and rot and are also suitable as tannins. [...] 'Vegetable tannins such as those from rhubarb roots, oak or mimosa bark have been known to man for a long time. […] But it could never replace the 400,000 tons of chrome tanning agent that is required for tanning worldwide every year. [...]. ' This is different with the patented olive tanning agent: when the olives are harvested and the trees are cut back, hundreds of thousands of tons of leaves are produced each year, most of which are burned as waste. ”Issue 10/2014, loaded on November 7, 2016
- K. Fuchs, M. Fuchs, L. Derichs: fascination leather . 2008.
- Wet Blue. In: Leder-Info.de. LEDERZENTRUM GmbH, accessed on March 1, 2018 .
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- See Andrea Jördens, Sarah Kiyanrad, Joachim Friedrich Quack: Leder . In: Michael Ott, Thomas Meier, Rebecca Sauer (Eds.): Materiale Textkulturen. Concepts - materials - practices (= material text cultures ). tape 1 . De Gruyter, Berlin / Boston / Munich 2015, ISBN 978-3-11-037128-4 , pp. 323-335 .
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