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Back (leather)
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Leather made from the main portion
of hide, obtained by cutting off the two bellies.
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Back (of animal)
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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.
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Bacteria
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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.
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Bacterial damage
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Hides
and skins damaged and rendered evil-smelling by bacterial damage.
See: Putrefaction.
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Bactericide
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Agent or treatment that specifically
kills bacteria.
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Bag tannage
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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.
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Bagginess
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Development
of a pouched or bag-like area in leather owing to excessive
plastic stretching of the leather.
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Bagging test
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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.
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Bale
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Closely pressed package of goods,
such as hides or skins, bound together with cord, wire, plastic
hoop, etc., ready for storage or transportation.
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Balling up
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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.
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Band
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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.
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Band damage
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Caused
by metal band used to bale up raw skins for transport.
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Bandknife
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Long, flexible, continuous knife
of a splitting machine.
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Barbed wire
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Wire to which sharp, protruding,
wire points are fixed at intervals. Mostly used around an enclosure.
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Bark-tan (v); bark tanning
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Tannage based mainly upon the
tannins contained in the bark of trees, the leather in process
coming in contact with the raw bark.
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Base coat
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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.
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Base dyeing
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Dyeing of a leather to a suitable
colour before the final dyeing or the application of a pigmented
finish.
See: Sandwich dyeing.
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Base lacquer
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First of the lacquer coats applied
in the manufacture of patent leather.
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Basement membrane
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Continuous thin film of specialised
extracellular material which physically separates cells from
the surrounding connective tissue.
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Basic chromium sulphate
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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.
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Basic dyestuff
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Dyestuff with a dyeing cation,
often pasted with acetic acid to assist dissolution.
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Basicity
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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).
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Basification
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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).
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Basify (v); basifying
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To increase the pH
of a chromium tanning bath or salt to increase the basicity.
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Basil
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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.
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BAT
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See: Best Available Technique.
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Batch
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Number
of items forming a group or dealt with together; using or dealt
with in batches, not as a continuous flow.
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Bate
|
Natural material, or a synthetic
mixture, which by microbiological and/or enzymatic action dissolves
and/or modifies certain protein components of the skin.
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Bate (v); bating
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To treat unhaired and limed pelt
with a bate.
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Bath
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Liquor in which a treatment is
given or a vessel for such a liquor.
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Beam
|
Convex structure, fixed at an
angle to the ground, over which suitably prepared hides or skins
are placed for unhairing, fleshing or scudding.
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Beamhouse
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Section of the tannery where
hides or skins are prepared for tanning, which includes the
operations of soaking, unhairing, fleshing and deliming etc.
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Beating
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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.
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Beaver lamb
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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.
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Bellows hide
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Curried, flexible and air-proof
leather made from split hide.
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Belly
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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.
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Belly grain
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Tanned outer (hair or grain)
layer split from a belly.
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Belly grain
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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.
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Belly strain
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Mechanical
damage caused to skins when they are pulled from the carcass.
See: Butcher strain.
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Belt filter
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Filtration of sludge of a suitable
consistency which is trapped between two filter belts and compressed
through a system of rollers.
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Belt leather
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Leather used for waist belts
as distinct from "transmission belting".
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Belting lace
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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.
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Bend
|
Half of a cattle hide butt, obtained
by dividing it along the line of the backbone.
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Best Available Technique (BAT)
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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.
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Binder
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Material used in finish preparations
to achieve film formation and to fix pigments and other additives
on the leather surface.
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Binder leather
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Vegetable tanned or chrome re-tanned
butt leather of uniform thickness, dressed or impregnated to
give it heat or abrasion resistance.
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Bio-assay
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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.
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Biochemical Oxygen Demand (BOD)
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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.
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Biocide
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Agent or treatment that specifically
kills micro-organisms.
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Biodegradation
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Molecular degradation of organic
matter resulting from the complex action of living organisms
ordinarily in an aqueous medium.
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Biofilter
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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.
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Biomass
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Total mass of living matter in
a given body of water. Activated sludge (unit g/l) is an example
of biomass.
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Birch tar oil
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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.
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BIT
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See: 1,2-benzisothiazolin-3-one.
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Blackening (of vegetable-tanned leather)
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Operation of staining or dyeing
vegetable tanned leather black.
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Bleach (v); bleaching
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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.
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Bleaching agent
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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.
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Bleaching extract
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Vegetable tanning extract, usually
heavily sulphited and containing additives, such as acids and
water-soluble oils, used for bleaching vegetable tanned leather.
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Bleaching tannin
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Vegetable, or synthetic, tanning
agent having the ability to render a leather paler in colour.
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Bleeding
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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.
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Bleeding of tannin
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Giving up of tannin in contact
with water.
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Blend (v); blending
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Mix together and make into a
more or less homogenous product various liquids, or powdered
or granulated solids.
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Blend (v); blending
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To apply a dye solution to the
hair coat in undyed furskins, to accentuate, level or slightly
modify the natural colour.
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Blind grain
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Grain
enamel that has been damaged by bacterial, mechanical or chemical
action. See: Abraded or low grain.
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Blind rib
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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.
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Blocking marks
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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.
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Blood
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Ox blood used as non-thermoplastic
binder in finish preparations. Added to black or dark coloured
leather improves the depth of colour and brilliance.
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Blood albumen
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Evaporated and dried blood serum,
after removal of fibrin and corpuscles.
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Blood vessels
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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.
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Bloom
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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.
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Bloom (finishes)
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Dullness
of the finish or an uneven refraction of light within the film.
Note:
Mild fatty spue or interaction between dyes and finish coat.
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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.
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Blotchy
|
Uneven
application of finish by spray guns.
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Blow fly strike
|
Scar or
open wound left on sheepskin by blow fly attack.
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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.
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Blushing
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White
haze causing dulling of the finish caused by the absorption
of moisture because of cooling from rapid evaporation of solvents
in the finish.
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Board (v); boarding
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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.
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Boarded grain
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Grain pattern developed by boarding
leather by hand or machine
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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.
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Boardy leather
|
Leather
that is stiffer than it should be.
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BOD
|
See: Biochemical Oxygen Demand.
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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.
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Boiling point
|
Temperature at which the tension
vapour of the liquid is equal to the external pressure applied
to it.
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Bond
|
The way two atoms
or groups link themselves. Note: Chelate, co-ordination, covalent,
cystine, disulphide, electrovalent, ester, hydrogen, interchain,
ionic, labile, peptydic.
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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.
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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.
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Bound lipid
|
Lipid chemically combined with
protein matter of the skin.
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Bound water
|
Water held in a material by forces,
as hydrogen bonds between it and polar groups.
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Bovine leather
|
Leather made from bovine animals
such as ox, heifer, cow, steer, zebu, etc.
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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.
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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.
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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.
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Brand
|
Identification
mark on the hide or skin of the animal which damages the grain.
Applied by hot iron or chemical or freeze branding.
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Brasilin
|
Colourless substance, which is
oxidised to the brownish-red dye brasilein.
Note: Brasilin is present in
red woods as a glucoside.
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Break
|
Pattern of more or
less fine creases formed when certain leathers, for example,
box calf, are bent, grain inwards.
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Breaking load
|
Force required to
break a material of a specified size and shape under specific
conditions, for example, leather.
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Bridge
|
Chemical bond that
links two different parts of a compound or polymer chain. Note:
Cystine, ester, oxo.
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Bridging
|
Link between two
molecules or groups with a group or an atom. Note: Hydrogen
bridge, disulphide bridge in keratin, methylene bridge, etc.
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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.
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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.
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Brightness-dullness value
|
Measure between the amounts of
incident white light reflected and scattered, and that absorbed
by a coloured material.
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Brilliance
|
Ability of a finished leather
surface to scatter and/or to reflect a high proportion of the
incident light.
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Brine
|
Water which contains salt at
a high concentration.
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Brine (v); brining
|
Salt-curing of hides by immersion
in a saturated salt solution.
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Brine conditioning
|
Effective control of the brining
operation, ensuring solution remains saturated, clean, grease-free
and free from micro-organism.
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Brined hide
|
Hide cured by immersion in a
saturated salt solution, drained and sometimes salted-down with
solid salt.
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Brining drum
|
Drum for brine curing of hides.
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Bristle
|
Short, stiff hair, especially
from hogs.
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Brittleness
|
Property of a leather
breaking suddenly, completely throughout its thickness, when
bent to a comparatively small extent.
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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.
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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.
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Brush (v); brushing
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