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Back (leather)	Leather made from the main portion of hide, obtained by cutting off the two bellies.
Back (of animal)	Main portion of hide, obtained by cutting off the two bellies. Note: In North America a back is a half cattle hide (or side) after the removal of the head and belly.
Bacteria	Bacteria are the smallest organisms that can complete their life cycle independently. They lack a nucleus and membrane-bound organelles. They may be autotrophic or hetrotrophic and occur in a wide range of environments. They are abundant on the remains of dead plants and animals and some cause disease in other living organisms. Bacteria are also responsible for such process as fermentation and decomposition.
Bacterial damage	Hides and skins damaged and rendered evil-smelling by bacterial damage. See: Putrefaction.
Bactericide	Agent or treatment that specifically kills bacteria.
Bag tannage	Mode of tannage, formerly used for Morocco leather, in which the prepared skins are sewn into bags, grain outwards, filled with a slurry of sumac and some air, tied at the opening, floated in a sumac liquor for a period and finally removed and piled upon each other to force the liquor through the skin.
Bagginess	Development of a pouched or bag-like area in leather owing to excessive plastic stretching of the leather.
Bagging test	Test to evaluate the deformation of the leather. For example, in the area of a garment or armchair where the leather is subjected to a stretching without restoring the original form.
Bale	Closely pressed package of goods, such as hides or skins, bound together with cord, wire, plastic hoop, etc., ready for storage or transportation.
Balling up	Forming of small balls when a resin finish is applied by padding or brushing. Usually caused by the presence of buffing dust or to poor mechanical shear of the resin. See: Pilling.
Band	1. Strip of material, such as leather, used to seal junction parts of machines or apparatus. 2. More or less wide zone of a spectrum absorbed or emitted by a material.
Band damage	Caused by metal band used to bale up raw skins for transport.
Bandknife	Long, flexible, continuous knife of a splitting machine.
Barbed wire	Wire to which sharp, protruding, wire points are fixed at intervals. Mostly used around an enclosure.
Bark-tan (v); bark tanning	Tannage based mainly upon the tannins contained in the bark of trees, the leather in process coming in contact with the raw bark.
Base coat	Depending on the type of leather the base coat provides the first coat for all subsequent finishes and top coats. Its purposes are       correction of the varying absorbing capacities in the different sections of the hide, levelling and filling effect and improvement of adhesion between the leather surface and all following coats.
Base dyeing	Dyeing of a leather to a suitable colour before the final dyeing or the application of a pigmented finish. See: Sandwich dyeing.
Base lacquer	First of the lacquer coats applied in the manufacture of patent leather.
Basement membrane	Continuous thin film of specialised extracellular material which physically separates cells from the surrounding connective tissue.
Basic chromium sulphate	Salt obtained by treating normal chromium sulphate Cr2(SO4)3, in the form of chrome alum, with an alkaline substance such as sodium carbonate, or by treating a suitable mixture of dichromate and sulphuric acid with an organic substance, such as glucose. The compositions of 33% and 66% basic salts can be represented as Cr2 (OH) 2 (SO4) 2 and  Cr2 (OH) 4SO4. Used in chrome tanning.
Basic dyestuff	Dyestuff with a dyeing cation, often pasted with acetic acid to assist dissolution.
Basicity	Relationship between chromium atoms and the acid radicals (or the basic hydroxyl groups) in a chromium compound. Usually it is expressed as the percentage ratio between the number of chromium atoms and the maximum number of -OH which is possible to associate with them in a compound varying from 0% in the chrome sulphate to 100% in the chrome hydroxide Cr(OH)3. (Basicity percentage or Schorlemmer).
Basification	Process of rendering a chrome liquor, or other mineral tanning agent, more basic, either before use or during tannage, by addition of a solution of an alkaline substance (sodium bicarbonate or carbonate).
Basify (v); basifying	To increase the pH of a chromium tanning bath or salt to increase the basicity.
Basil	Unsplit pelt, usually of a woolled sheepskin, vegetable tanned. Note: In the UK, this leather is sometimes called "full sheep". In Germany the term is not applied to rough tanned sheep leather, but is also used as a description of origin in the case of the woolled sheepskin.
BAT	See: Best Available Technique.
Batch	Number of items forming a group or dealt with together; using or dealt with in batches, not as a continuous flow.
Bate	Natural material, or a synthetic mixture, which by microbiological and/or enzymatic action dissolves and/or modifies certain protein components of the skin.
Bate (v); bating	To treat unhaired and limed pelt with a bate.
Bath	Liquor in which a treatment is given or a vessel for such a liquor.
Beam	Convex structure, fixed at an angle to the ground, over which suitably prepared hides or skins are placed for unhairing, fleshing or scudding.
Beamhouse	Section of the tannery where hides or skins are prepared for tanning, which includes the operations of soaking, unhairing, fleshing and deliming etc.
Beating	Process of removing loose salt and foreign matter from a salted hide prior to weighing by beating, banging or shaking it in an  agreed manner. Note: By beating the hair and flesh sides once on the ground, or by banging it against a “horse” or “buck” or pack of hides. See: Tare.
Beaver lamb	Sheep or lambskin with short fine wool, which has been dressed with the wool on, dyed and finished by a process giving a weather-resistant straightness and brightness to the wool. See: Shearling.
Bellows hide	Curried, flexible and air-proof leather made from split hide.
Belly	1. The part of each side of a sheepskin or cattle hide which cover half the animal’s underside and the upper parts of the fore and hind legs; 2. The extreme left or right side of a cattle hide removed by cutting along a line parallel to the backbone line and such a distance from it determined for an individual hide by noting the change in feel from the denser structure of the crop, or butt, to the looser structure of the belly (USA). Includes belly middle, axillae or leg-pits  and shanks.
Belly grain	Tanned outer (hair or grain) layer split from a belly.
Belly grain	Damage caused by irritation by urine and dung, sometimes found on the bellies and upper thighs of calf skins and shown in the leather as unevenly roughened, or eroded, grain areas.
Belly strain	Mechanical damage caused to skins when they are pulled from the carcass. See: Butcher strain.
Belt filter	Filtration of sludge of a suitable consistency which is trapped between two filter belts and compressed through a system of rollers.
Belt leather	Leather used for waist belts as distinct from "transmission belting".
Belting lace	Chrome tanned back, about 2.5 mm thick, heavily dressed with natural grease, suitable for cutting into strips for the purpose of joining transmission belting.
Bend	Half of a cattle hide butt, obtained by dividing it along the line of the backbone.
Best Available Technique (BAT)	EU Definition: The most effective and advanced stage in the development of activities and their methods of operation which indicate the practical suitability of particular techniques. This will provide, in principle, the basis for emission limit values designed to prevent and, where that is not practicable, to reduce emissions and the impact on the environment as a whole. It also takes account of economic considerations.
Binder	Material used in finish preparations to achieve film formation and to fix pigments and other additives on the leather surface.
Binder leather	Vegetable tanned or chrome re-tanned butt leather of uniform thickness, dressed or impregnated to give it heat or abrasion resistance.
Bio-assay	Method for quantitatively determining the concentration of a substance by its effect on the growth of a suitable animal, plant or micro-organism under controlled conditions.
Biochemical Oxygen Demand (BOD)	The mass concentration of dissolved oxygen consumed under specified conditions by the biological oxidation of organic and/or inorganic matter in water. Note: BOD5 is the mass concentration of dissolved oxygen consumed during 5 days.
Biocide	Agent or treatment that specifically kills micro-organisms.
Biodegradation	Molecular degradation of organic matter resulting from the complex action of living organisms ordinarily in an aqueous medium.
Biofilter	Attached-growth reactor using as bacterial support a granular material which ensures both the filtration of raw water and the biological degradation of the pollution it contains.
Biomass	Total mass of living matter in a given body of water. Activated sludge (unit g/l) is an example of biomass.
Birch tar oil	Oil obtained from the  bark of birch trees by dry distillation. Additive in fatliquors and finishing formulations to cover up offensive odour and to give a  pleasant “leather” smell.
BIT	See: 1,2-benzisothiazolin-3-one.
Blackening (of vegetable-tanned leather)	Operation of staining or dyeing vegetable tanned leather black.
Bleach (v); bleaching	To deprive of colour in a coloured material, as by exposure to the sun and weather or chemicals, in such a way as to remove, or lighten to the maximum its colour. To become colourless, pale or white.
Bleaching agent	Compound used in the process of making the colour paler in leather and textile fibres and fabrics, by treatment with chemicals or exposure to the sun and weather.
Bleaching extract	Vegetable tanning extract, usually heavily sulphited and containing additives, such as acids and water-soluble oils, used for bleaching vegetable tanned leather.
Bleaching tannin	Vegetable, or synthetic, tanning agent having the ability to render a leather paler in colour.
Bleeding	Passage of a component in solution from the interior of a solid onto the surface or onto another solid in contact with it. Note: Dye from leather into a resin top finish.
Bleeding of tannin	Giving up of tannin in contact with water.
Blend (v); blending	Mix together and make into a more or less homogenous product various liquids, or powdered or granulated solids.
Blend (v); blending	To apply a dye solution to the hair coat in undyed furskins, to accentuate, level or slightly modify the natural colour.
Blind grain	Grain enamel that has been damaged by bacterial, mechanical or chemical action. See: Abraded or low grain.
Blind rib	Rib pattern which is generally not visible in the raw but becomes apparent, mainly in the neck and shoulder, when the skin is held up to the light in the limed state. See: Rib lines.
Blocking marks	Occurs when leather is piled finish to finish, flesh to flesh and the finish surface adheres, causing dull areas or even coats of finish being pulled away when the leather is separated.
Blood	Ox blood used as non-thermoplastic binder in finish preparations. Added to black or dark coloured leather improves the depth of colour and brilliance.
Blood albumen	Evaporated and dried blood serum, after removal of fibrin and corpuscles.
Blood vessels	Tube through which blood circulates in an animal body. When visible in leather the cause is usually poor bleeding or staleness, but can be breed related. See: Veins.
Bloom	Pale yellow to brown precipitate, consisting mainly of ellagic acid together with chebulinic acid, formed on the surface of, or within, vegetable tanned leather, or in a tan-pit when using liquors based upon ellagitannins, such as valonia, divi-divi, myrabolams, algarobilla, as well as oak bark.
Bloom (finishes)	Dullness of the finish or an uneven refraction of light within the film. Note: Mild fatty spue or interaction between dyes and finish coat.
Bloom-forming tannin	Tanning material, or tannin, whose solution forms bloom on standing, (algarobilla, divi-divi, chestnut wood, myrabolams, oak bark and valonia). See: Bloom.
Blotchy	Uneven application of finish by spray guns.
Blow fly strike	Scar or open wound left on sheepskin by blow fly attack.
Blue scale	Method to evaluate changes in the colour of a material, such as leather, due to natural or artificial light effect. It includes 8 degrees of change (8 = no change, 1 = total decolouring or change). See: Grey scale.
Blushing	White haze causing dulling of the finish caused by the absorption of moisture because of cooling from rapid evaporation of solvents in the finish.
Board (v); boarding	To work the grain side of a leather by hand with a cork-covered board or by a machine in order to restore and develop the natural grain.
Boarded grain	Grain pattern developed by boarding leather by hand or machine
Boarded leather	Leather that has been softened and the surface of which has been lightly creased by folding grain to grain and then working the fold across the leather to and fro by hand boarding or by means of a boarding machine. See: Box calf; box side; morocco; willow calf; willow side.
Boardy leather	Leather that is stiffer than it should be.
BOD	See: Biochemical Oxygen Demand.
Boil (v); boiling	1. Transition of a substance from the liquid to the gaseous phase, taking place at a single temperature in pure substances and over a range of temperatures in mixtures. 2. Boiling test - empiric test to evaluate the resistance to temperature by dipping a piece of leather in boiling water and measuring the shrinkage of the area or of the size.
Boiling point	Temperature at which the tension vapour of the liquid is equal to the external pressure applied to it.
Bond	The way two atoms or groups link themselves. Note: Chelate, co-ordination, covalent, cystine, disulphide, electrovalent, ester, hydrogen, interchain, ionic, labile, peptydic.
Bookbinding leather	Leather of suitable thickness, durability and lightfastness, made mostly from sheep, goat, calf, pig and deer skins, usually vegetable tanned, but sometimes, specially in former times, alum-dressed. Note: Used to bind books, documents and similar articles.
Bottom dyeing	Dyeing base, the lowest part, of a leather  to a desired colour before the application of a pigment finish or in final stage of dyeing.
Bound lipid	Lipid chemically combined with protein matter of the skin.
Bound water	Water held in a material by forces, as hydrogen bonds between it and polar groups.
Bovine leather	Leather made from bovine animals such as ox, heifer, cow, steer, zebu, etc.
Bovine Spongiform Encephalopathy (BSE)	Bovine Spongiform Encephalopathy is a newly (1986) diagnosed disease of cattle that has evolved rapidly into one of  the major veterinary - and human - medicine problems of the past few decades. It is included in the group of Transmissible Spongiform Encephalopathies (T.S.E’s). T.S.E.’s are a class of rare brain diseases associated with the accumulation of abnormal proteins (Prion’s Theory) in the brains of man and animals. They are characterised by very slow development and the diseases are always fatal. The most common disease of this type is sheep scrapie ( first reported in 1732), the most publicised is BSE or “Mad Cow” disease (1986). Since March 1996 BSE is related to the new variant of Creutzfeld - Jacob disease (CJD), a new degenerative fatal disease.
Box calf	Full chrome tanned calf leather, black or coloured, smooth or boarded. Note: In the UK it must be black. When it is in other colours, see willow calf.
Box side	Full chrome or combination tanned leather made from cattle hide sides, black or coloured, smooth or boarded. Note: In France the leather may also be synthetic tanned. In the UK any tannage may be used but the leather must be black. When it is in other colours, see willow side.
Brand	Identification mark on the hide or skin of the animal which damages the grain. Applied by hot iron or chemical or freeze branding.
Brasilin	Colourless substance, which is oxidised to the brownish-red dye brasilein. Note: Brasilin is present in red woods as a glucoside.
Break	Pattern of more or less fine creases formed when certain leathers, for example, box calf, are bent, grain inwards.
Breaking load	Force required to break a material of a specified size and shape under specific conditions, for example, leather.
Bridge	Chemical bond that links two different parts of a compound or polymer chain. Note: Cystine, ester, oxo.
Bridging	Link between two molecules or groups with a group or an atom. Note: Hydrogen bridge, disulphide bridge in keratin, methylene bridge, etc.
Bridle leather	Strong, flexible type of harness leather, made from ox or cow hide, vegetable tanned and curried, of reasonably uniform thickness with a plain finish and a close shaved flesh.
Brightening dye	Selected anionic dye which is added to the pigment base coat finish or to top coat preparations in order to enhance brilliance or the aniline effect.
Brightness-dullness value	Measure between the amounts of incident white light reflected and scattered, and that absorbed by a coloured material.
Brilliance	Ability of a finished leather surface to scatter and/or to reflect a high proportion of the incident light.
Brine	Water which contains salt at a high concentration.
Brine (v); brining	Salt-curing of hides by immersion in a saturated salt solution.
Brine conditioning	Effective control of the brining operation, ensuring solution remains saturated, clean, grease-free and free from micro-organism.
Brined hide	Hide cured by immersion in a saturated salt solution, drained and sometimes salted-down with solid salt.
Brining drum	Drum for brine curing of hides.
Bristle	Short, stiff hair, especially from hogs.
Brittleness	Property of a leather breaking suddenly, completely throughout its thickness, when bent to a comparatively small extent.
Bronze (v); bronzing	Unwanted metallic sheen or lustre often associated with build up of basic dyestuff on the surface of the leather. Can also occur with poorer quality inorganic pigments.
Bruise (v); bruising	Crowding or bumping of the animals or the use of a whip or club can cause a haemorrhage in the skin and underlying tissue. Although difficult to see from the grain side because of the hair, bruises can be visible from the flesh due to excess blood in the affected area. This can quickly putrefy and become a blemish or weak spot.
Brush (v); brushing	Leather is passed between rotating, stiff brushes to bring up the nap or to remove any surplus dust caused by buffing.       Hand brushes or brushing machines are also used for the application of finishes for splits or coarse-fibred leather.
Brush dyeing	Apply a dye solution to a leather surface by brushing.
Brush dyeing	Dyeing of the hairs of a furskin by applying a dye solution with a brush.
Brush marks	Pattern of the brush used for applying a finish. May be caused by using finishing systems that “set up” too rapidly or by using coarse grade applicators.
Brush mordanting	Process of applying a mordant to a leather surface with a brush.
Brush mordanting	Application of a mordant solution to the top hair of a furskin, rather than the underfur, by means of a brush.
Brush off	Special effect, giving contrasting colours. The top coat of the finish is partially removed to reveal the underlying, contrasting colour.
BSE	See: Bovine Spongiform Encephalopathy.
Bubble (v); bubbling	Air trapped in the surface finish of the leather, either as intact or broken bubbles, giving an uneven appearance to the film.
Bubble diffuser	Aeration system by blowing compressed air into the liquid mass at depths varying from 1 to 10 metres.
Buck	Male deer, antelope, hare, rabbit or goat.
Buckskin	Suede leather made from deer skin from which the grain has been removed, usually by frizing. It is generally tanned with fish oil or aldehyde or a combination of both and may be finished on the flesh or the frized grain side.
Buff (v); buffing	Abrade or grind a leather surface, especially the grain surface, by a moving band of abrasive paper or cloth.
Buffed leather	Leather from which the top surface of the grain has been removed by an abrasive or bladed cylinder or, less generally, by hand. Note: In the case of upholstery leather the buffing process is invariably carried out by the machine though it is sometimes incorrectly described as "hand buffed". See: Corrected grain; buff (v); buffing.
Buffer	Solution prepared to reduce and resist changes in pH (in the concentration of H3O+).
Buffing depth	Regulation of the depth of buffing to achieve the desired effect on the finished leather.
Buffing dust	Dust obtained from the buffing operation.
Buffing ground	Special grounding agents, such as mucilages or synthetic resin dispersions, to improve the buffing properties of leather, especially for corrected grain leather.
Bundle	Group of parallel fibres.
Burns	Acid or alkali burns usually caused by lack of movement in the process vessel with a concentration of the chemical damaging the grain. Also high temperatures causing gelatinisation. Machinery can cause friction burns. See: Glazing.
Burrs	Burrs, seeds and prickles from plants caught in the wool of sheep. These can penetrate the grain causing permanent damage.
Butcher strain	Mechanical damage caused to skins when they are pulled from the carcass. See: Belly strain.
Butt	Leather from that part of the hide left after removal of the bellies and shoulders.

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