Leather

Department of Leather Engineering, KUET, Khulna-9203.

Leather
Leather is a durable and flexible material created
by tanning animal rawhide and skin, often cattle hide. It can be produced
at manufacturing scales ranging from cottage industry to heavy industry.
People use leather to make various goods—including clothing (e.g.,
shoes, hats, jackets, skirts, trousers, and belts), bookbinding, leather
wallpaper, and as a furniture covering. It is produced in a wide variety of
types and styles, decorated by a wide range of techniques.
S. M. Murshidur Rahman, Khulna University of Engineering & Technology (KUET).

Properties of leather
The physical properties which make leather a unique and valuable material
for upholstery purposes includes:
• High tensile strength.
• Resistance to tear.
• High resistance to flexing.
• High resistance to puncture.
• Good heat insulation.

• Leather contains a great deal of air, which is a poor conductor of heat.
This is an important comfort consideration.
• Permeability to water vapour: Leather fibres will hold large quantities of
water vapour. This property enables leather to absorb perspiration, which
is later dissipated. A significant factor in comfort.
• Thermostatic properties: Leather is warm in winter and cool in summer.
• Mouldability (Elasticity and plasticity): Leather can be moulded and will
retain its new shape. It has both elastic and plastic properties in wear.

• Resistance to wet and dry abrasion: These properties, concerned with wear and
maintenance, are controlled by the tannage and surface finish. These have now
reached high levels of excellence.
• Resistance to fire: Leather is inherently resistant to heat and flame.
• Resistance to fungi: Leather is resistant to mildew.
• Resistance to chemical attack: The atmosphere of modern cities is polluted from
the burning of carbon fuels with sulphur dioxide gas, which can accelerate the
deterioration of leather. Modern leathers are tanned and dressed to resist these
harmful chemicals.

Advantages of Leather
Leather is a wonderful material with many uses. It's unique properties and
characteristics make it the ideal choice for many different applications. It has a
high tensile strength and is resistant to tearing, flexing and puncturing. This helps
leather items last for a long time while retaining their look and feel.
• It is a good heat barrier and provides excellent heat insulation. Leather contains
a large amount of air and air is a poor conductor of heat. This makes leather a
very comfortable item for the human skin.
• It is able to hold large quantities of water vapor such as human perspiration and
then dissipate it later. This makes leather a comfortable item to wear or sit on.

• Leather's thermostatic properties make it warm in the winter and cool in the
summer. This makes leather comfortable to wear.
• It can be made to stiffen or can be made to be flexible. It can be molded into a
certain shape and then remolded into another shape later.
• Leather is resistant to abrasion in both wet and dry environments. This makes
leather an excellent protector of human skin.
• It is resistant to heat and fire. It is also resistant to fungal growth such as mildew.
• It consists of many fibers that are breathable. This breathability makes it very
comfortable to wear in any climate.

• Leather can be dyed many different colors that makes it attractive in the
production of leather clothing, as a cover for furniture and for many other
color sensitive applications.
• It is can be soft and supple. Leather clothing becomes a literal second skin. It
warms to your body temperature. It is not itchy and does not scratch. It is non-
irritating to the skin.
• Leather is a fantastic material with excellent physical properties that enables it
to be used in many diverse applications from furniture to clothing.

Types of leather
Leather are generally classified:
• According to source
• According to surface grain
• According to tanning
• According to finish

According to source
• Cow hide
• Goat Skins
• Sheep Skins
• Mule
• Pig Skins
• Deerskin
• Bison or Buffalo hide
• Ostrich leather
• Kangaroo leather
• Eel skin
• Crocodile
• Horse
• Snake skin
• Seal Skin
• Shark skin
• Lizard
• Walrus
• Shagreen
• Yak
• Whale etc.

Cow leather
Bovine or Cowhide leather is the most abundant and common leather source.
Cowhide offers maximum value for texture, appearance, durability, and comfort.
Cowhide is easy to care for, the least expensive due to its availability and is dirt
and water resistant. Cowhide is one of the heaviest leathers making it very tough
wearing and durable featuring a pebble grain appearance. Although it can be
somewhat stiff, cowhide breaks in easily. Cow leather is used for virtually every
leather product including outerwear, jackets, casual and biker style coats, gloves,
belts, saddles, bags, furniture, straps, shoes, boots, and upholstery.

Cow leather
Calfskin is used to produce a high quality, attractive leather with a soft,
fine feel. Calfskin has a smooth surface, which is dense, lightweight,
and abrasion resistant. Calfskin takes on high luster with use and is used
in bookbinding, dresses, shoes, and straps.

Cow leather

Goat Skins
They have an area of 4 to 8 sq. ft. with a coarse fibrous structure varying
between butt and belly. Substance is thick. Vegetable tanned goat skins are
used as linings.
Goat skin leather is an economical, strong and durable, with a smooth fine
grain. Goatskin is slightly softer and tougher than cow leather and is
lightweight, comfortable, supple, flexible, and water-resistant. Pigskin is used
to manufacture to gloves, casual shoes, coats, vests, bookbinding, wallets,
belts, and protective clothing. Kidskin is a very soft leather made from the
hide of a young goat.

Goat skin

Sheep Skins
Sheep skins have loose fibrous structure, loose grain surface and light
substance with a soft feel. They have an area of 2 to 9 sq.ft and are suede
finished. The wool sheep skins can be sheared. Sheep skins are used for
linings.
Sheep skin leather is extremely soft, comfortable, and pliable. The finely
grained leather is thin and supple with a buttery texture. Sheep leather is
lightweight, warm and delicate and absorbs water well.

Sheep skin

Pig Skins
Pig skin is the leather fabric made from a pig or a hog. Pig or hog skin
leather is a dense leather similar to cowhide with a soft and supple feel and
very good durability. Pigskin is very pliable, comfortable and water
resistant with a high lanolin content to keep the glove soft after getting
wet. Pigskin is used to manufacture work gloves, shoes, boots, sportswear,
handbags, saddle seats, belts and apparel such as, shirts, blazers, and
jackets. Despite their nickname, footballs are actually made of cowhide.

Pig Skin

Deerskin
Deerskin is one of the toughest leathers available due to the thorny nature
of the animal’s natural habitats. Deerskin leather’s high tensile strength is
abrasion resistant and offers high durability. Deerskin is extremely soft and
comfortable with a spongy feel. It is lightweight, water-friendly, and
stretchy and fits well. Deerskin is more expensive and used to manufacture
gloves, shirts, dresses, hats, slippers, jackets, overcoats, sporting
equipment, handbags, wallets, and upholstery.

Deerskin

Bison or Buffalo hide
Buffalo hide is a heavy duty and durable leather and very value priced.
This leather is rugged and strong, yet soft and supple with a rubber
waxy feel. Buffalo leather features thicker fibers which are more widely
spaced and evident hair follicles creating a pebbly appearance. Bison
leather is used to make furniture, shoes, belts, bookbinding, rugs,
gloves, jackets, and baseball gloves .

Buffalo leather

Ostrich leather
Ostrich leather is much rarer, but is one of the finest and most durable
leathers. Ostrich leather is luxurious, soft, supple, and thick featuring an
exotic goose bump appearance from the large feather quill follicles. Ostrich
leather is popular in luxury fashion and is used to make boots, footwear,
upholstery, accessories, clothing, luggage, purses, wallets, and briefcases.

Ostrich leather

Eel skin
Eel skin is a very thin and elegant, which is not very strong. Eel skin
leather can be durable but requires maintenance if exposed to elements.
Eel skin is soft, shiny, and smooth with horizontal pin-stripe patterns.
This leather is actually produced from a slimy eel-like fish called the
inshore hagfish, which is caught in the wild. Eel skin becomes softer
and suppler with use and is used to make wallets and handbags.

Eel leather

Crocodile and alligator skin
Crocodile and alligator skin renders a very attractive and fashionable
leather. The leather is strong, supple, durable and very expensive. A bony
layer within the skin adds a protective shield, while a dimple on each
scale makes a very exotic look. Crocodile and alligator leather is used to
make luxury goods, handbags, wallets, boots, belts, and briefcases.

Crocodile and alligator skin

Snakeskin
Snakeskin is typically produced from venomous sea snakes which are
commercially farmed. The leather is delicate, thin, soft and flexible,
while the fine small hexagon scales produce exotic detailed grains.
Snake skin leather is used to make boots, wallets, and handbags.

Kangaroo leather
Kangaroo leather is lightweight, strong and flexible with high abrasion
resistance compared to cowhide. Ostrich leather can be cut into very thin
layers which remain strong and create lighter weight garments. Ostrich
leather is made from free range wild animals and is popular in soccer
footwear, as well as, bullwhips and apparel.

Kangaroo leather

Stingray or shagreen leather
Stingray or shagreen leather is very tough with a siliceous layer on the
surface, which makes it as durable as hard plastic. Stingray leather has a
beautiful appearance and wonderful feel, which is very strong. Stingray
leather scales even protect from fire damage. The leather is usually dyed
black and covered with tiny round bumps dyed white to highlight the
decoration. Stingray leather is used for clothing, furniture, wallets, belts,
purses, and briefcases.

Stingray or shagreen leather

Sealskin
Sealskin is the skin of a seal which has been hunted.
Seal skins have been used by aboriginal people for millennia to make waterproof jackets
and boots, and seal fur to make fur coats. Sailors used to have tobacco pouches made
from sealskin. Canada, Greenland, Norway, Russia and Namibia all export sealskin. It
was traditionally used to make Scottish sporrans.
The indigenous Inuit people argue that banning seal products is detrimental to their way
of life. However, there are many objections to the use of seal skin, fur and pelts, and it is
illegal to hunt seals in many countries, particularly young seals. The value of global
sealskin exports in 2006 was over 16 million Canadian dollars.

Sealskin

Mule skin
Mule skin has a higher density than steer which gives it a very distinct and
crisp sound profile. We have several different types of mule skin which
work perfectly for many different types of drums.
Mule skin has a very bright tone and sounds controlled and tight. Slaps are
amazingly crisp.

Mule skin

Horse/Equine skin
Equine skin conditions are often difficult to diagnose and frustrating to treat,
with causes ranging from fungus to allergens to who-knows-what.
The skin is the largest organ of your horse’s body. It provides a protective
barrier against the environment, regulates temperature, and gives your horse its
sense of touch. Depending on the species and age, the skin may be 12 to 24%
of an animal’s body weight. The skin has 3 major layers: the epidermis or
outermost layer, the dermis or middle layer, and the subcutis or innermost layer.
Other important components include skin appendages (such as hair and
hooves), and subcutaneous muscles and fat.

Horse/Equine skin

Lizard leather
Lizard leather scales are remarkably water proof, and provide excellent
protection from the elements. Pesky stains shan’t be nearly as much of a
threat to lizard skin as to other leathers, although this shouldn’t be your cue
to take it for granted. Those scales are rooted in place by a well lubricated
membrane beneath them, which they are charged with protecting. Should
that membrane dry up, the scales can pop off, which really doesn’t bode
well for the aesthetics. Try not to take lizard leather out under excessive
weather conditions, such as rain. If it does get wet, just blot up the moisture
with a dry, clean cloth or paper towel.

Lizard leather

Walrus leather
Leather produced from any fur bearing swimming mammal such as the
Atlantic walrus (Odobenus rosmarus), Pacific walrus (Odobenus abesus),
sea lion (Zalophus caliifornianus) or seal (Callorhinus alascanus). All are
called walrus leather because, once processed, the skins are difficult to
distinguish. Walrus hides are thick, tough, and smooth. Due to the scarcity
of the animals at the end of the 20th century, most commercial walrus
leathers were imitations made from embossed and
grained sheepskins, goatskins, or cowhides.

Walrus leather

Shark leather
Shark leather is world known for its rough, course texture. In the coarser
developments of shark skin, it has been used like sandpaper for polishing.
However, the finer tanned shark skins are used for shoes, handbags, and
other leather items. Highly sought after, these skins are by-products from
fishing villages and international cuisine.
All of our leather is coming from non-endangered and non-threatened
shark species and no CITES is required. Currently, we’re offering black fin
species in 1 to 4 oz thickness in a rough or soft-tanned presentation.

Shark leather

Human leather
Human leather is made from real full thickness human skin. Just like
animal leather products, produced from lesser animals, our raw human
skin is transformed into the finest grade human leather by using a
traditional tanning process. However, human leather is the finest grain
leather that is obtainable. It is free from defects and has the smallest
grain size which makes it the smoothest, softest leather on Earth.

Human leather

Tilapia fish leather

Chicken leather

Some other animal sources used for leather include boar, elk, donkey,
ox, whale, and yak.
Whale Donkey
Other sources of leather

Ox Yak

Elk
Boar

• Full grain
• Top grain
• Corrected grain
• Split
• Suede
• Nubuck
According to surface grain

Full-grain leather refers to hides that have not been sanded, buffed, or
snuffed (as opposed to top-grain or corrected leather) to remove
imperfections (or natural marks) on the surface of the hide. The grain
remains allowing the fiber strength and durability. The grain also has
breathability, resulting in less moisture from prolonged contact. Rather
than wearing out, it develops a patina during its expected useful lifetime.
High quality leather furniture and footwear are often made from full-
grain leather. Full-grain leathers are typically available in two finish
types: aniline, semi-aniline.
Full-grain leather

Full-grain leather

Top-grain leather
Top-grain leather (the most common type in high-end leather products) is
the second-highest quality. It has had the "split" layer separated away,
making it thinner and more pliable than full-grain. Its surface has been
sanded and a finish coat added, which produces a colder, plastic feel with
less breathability, and it does not develop a natural patina. It is typically
less expensive and has greater stain resistance than full-grain leather if the
finish remains unbroken.

Top-grain leather

Corrected-grain leather
Corrected-grain leather is any leather that has had an artificial grain
applied to its surface. The hides used to create corrected leather do not meet
the standards for use in creating vegetable-tanned or aniline leather. The
imperfections are corrected or sanded off, and an artificial grain embossed
into the surface and dressed with stain or dyes. Most corrected-grain leather
is used to make pigmented leather as the solid pigment helps hide the
corrections or imperfections. Corrected grain leathers can mainly be bought
as two finish types: semi-aniline and pigmented.

Corrected-grain leather

Split leather
Split leather is leather created from the fibrous part of the hide left once the
top-grain of the rawhide has been separated from the hide. During the
splitting operation, the top-grain and drop split are separated. The drop split
can be further split (thickness allowing) into a middle split and a flesh split.
In very thick hides, the middle split can be separated into multiple layers
until the thickness prevents further splitting. Split leather then has an
artificial layer applied to the surface of the split and is embossed with a
leather grain (bycast leather). Splits are also used to create suede.

Split leather
The strongest suedes are usually made from grain splits (that have the grain
completely removed) or from the flesh split that has been shaved to the
correct thickness. Suede is "fuzzy" on both sides. Manufacturers use a
variety of techniques to make suede from full-grain. A reversed suede is a
grained leather that has been designed into the leather article with the grain
facing away from the visible surface. It is not considered a true suede.

Split leather

Suede leather
Suede is a type of leather with a napped finish, commonly used
for jackets, shoes, shirts, purses, furniture and other items. The term comes
from the French "gants de Suède", which literally means "gloves
from Sweden". Suede is made from the underside of the animal skin, which
is softer and more pliable than, though not as durable as, the outer "skin"
layer.

Suede
Mostly used as an insole lining in our men's sandal range. As suede is
actually a type of leather it is also very expensive and adds a significant
amount to the cost of the shoe. Its benefits are also similar to that of
leather but limited to the fact that it is mainly an innersole material.

Suede leather

Nubuck leather
Nubuck is made of the grain side (topside) of the leather. After tanning and
dyeing it is sanded, so that it looks like ultra fine suede. Even though nubuck
and suede thus are fundamentally different, they must be treated and cared for
the same way. Nubuck often contains excess dye, as tanneries today are not
able to rinse after dyeing, to the same extent as previously, because of
environmental requirements.
This leather has clearly rough, Small, fine shreds is covering the surface. The
back side is rougher than the front. Very Soft. Very absorbent. Highly
sensitive to light. (Some colors are extremely light sensitive).

Nubuck leather

Suede vs Nubuck
Naturally, the outside of a hide is tougher than the inside of a hide. It has to
be in order to protect the animal from damage. Since nubuck is made from
the outside of the hide, accordingly it is more rough and tough and long-
lasting than suede. Suede is made from the “split” end of the hide and is
softer, more porous, and less resistant to scuffs and stains. But boy is it soft!
Suede is often used in the lining of gloves and shoes.
Keep in mind that although suede and nubuck are made from different parts
of an animal, their difference is only skin deep.

To make the nubuck, the outer layer of the calfskin is used, then the leather
has to be sanded from the outside of the skin. The nubuck is more
expensive than suede most of the time. This is because the outer layer of
calfskin, is tougher than the inner part used for the suede and therefore
logically is stronger and will last longer. However there is a counterpart to
the nubuck, because the nubuck is sanded from the outside, there maybe
some apparent natural imperfections of the leather.
Suede vs Nubuck

Some might find that the imperfections give character to the nubuck, but for
all the others, in order to offer a smooth and clean product, manufacturers
often dye and stain the nubuck.
In Contrary to the nubuck, the inner layer of the calfskin (or other animal
skins) are used to make the Suede. The suede is also sanded from the inner
side of the leather allowing a naturally smoother and cleaner product than the
nubuck. But as mentioned above this also implies that when compared to
nubuck, suede is not as resistant.
Suede vs Nubuck

Many believe that suede will be damaged if wet. Although it is not advised
to expose suede to too much water, your suede shoes won’t be ruined if
wet. If you can, avoid going out with suede on the rainy days, but if you do,
don’t worry your shoes will survive just fine. In fact suede does not require
much maintenance, treating your suede shoes with water proofing
products and brushing them regularly with a suede brush (the soft bristles,
never the wire) to maintain the nap, the actual fibers that gives suede its
character, will be enough.
Suede vs Nubuck

Nubuck is actually a type of suede and both are generally made of leather
like calfskin, although they may also be made from the hide of a sheep/lamb,
cow/calf, goat, or deer. At first sight, they both look and feel similar but are
in fact created and treated differently as seen previously. Both of these
leathers are created by sanding process, the nubuck being sanded from the
outside and the suede from the inside. Because of this difference, their is
wide price range between nubuck and suede, suede being the cheapest.
Suede vs Nubuck

When maintaining your suede or nubuck, it is important to pick the correct
brush for each. Since the nubuck is a harder material than suede, a nubuck
brush used on suede will damage the nap. On the other hand a suede brush
used on nubuck will have little to no effect.
Many believe that suede shoes are harder to maintain and more precious than
their shiny leather counterparts. This could not be further from the
truth. Suede and nubuck actually require less maintenance. These shoes do
not need to be shined and should never be shined, so say goodbye to
the weekly shinning chore.
Suede vs Nubuck

Suede vs Nubuck

According tanning
• Chrome tanned
• Vegetable tanned
• Alum tanned
• Aldehyde tanned
• Synthetic tanned
• Formaldehyde tanned
• Brain tanned
• Oil tanned
• Rose tanned
• Fur tanned
• Raw leather

Chrome-tanned leather
Chrome-tanned leather, invented in 1858, is tanned using chromium
sulfate and other chromium salts. It is more supple and pliable than
vegetable-tanned leather and does not discolor or lose shape as drastically in
water as vegetable-tanned. It is also known as wet-blue for its color derived
from the chromium. More exotic colors are possible when using chrome
tanning. The chrome tanning method usually only takes a day to finish, and
the ease and agility of this method make it a popular choice. However there
are environmental concerns with this tanning method. It is reported that
chrome-tanned leather adds up to 80% of the global leather supply.

Chrome-tanned leather

Vegetable-tanned leather
Vegetable-tanned leather is tanned using tannins and other ingredients
found in different vegetable matter, such as tree bark prepared in bark
mills, wood, leaves, fruits, and roots. It is supple and brown in color, with
the exact shade depending on the mix of chemicals and the color of the skin.
It is the only form of leather suitable for use in leather carving or stamping.
Vegetable-tanned leather is not stable in water; it tends to discolor, so if left
to soak and then dried it shrinks and becomes harder. This is a feature of oak
bark tanned leather that is exploited in traditional shoemaking.

In hot water, it shrinks drastically and partly congeals—becoming rigid,
and eventually brittle. Boiled leather is an example of this, where the
leather has been hardened by being immersed in hot water, or in
boiled wax or similar substances. Historically, it was occasionally used
as armour after hardening, and it has also been used for book binding.

Aldehyde-tanned leather
tanned leather is tanned using glutaraldehyde oroxazolidine compounds.
This is the leather that most tanners refer to as wet-white leather due to its
pale cream or white color. It is the main type of "chrome-free" leather, often
seen in shoes for infants and automobiles.

Aldehyde-tanned leather

Formaldehyde leather
Formaldehyde tanning (being phased out due to danger to workers and
sensitivity of many people to formaldehyde) is another aldehyde tanning
method. Brain-tanned leathers fall into this category, and are exceptionally
water absorbent.

Brain tanned leather
Brain tanned leathers are made by a labor-intensive process that uses
emulsified oils, often those of animal brains such as deer, cattle, and
buffaloes. They are known for their exceptional softness and washability.

Brain tanned leather

Oil tanned leather
This leather is water, stain and perspiration resistant, and has a more natural
look and feel because less finishing materials have been applied, allowing
its natural beauty to shine through. Oil-tanned leather is exceptionally
durable and has been used to build countless work boots throughout Red
Wing’s 110+ year history. Oil tanned leather is unique because it has special
oils & waxes applied during the tanning process to give the leather a very
soft and supple feel that is resistant to water and other elements.

The leather has a wonderful full bodied hand that is the perfect
combination of softness and rugged durability for bags, boots, chaps, and
more!
Characteristics: Very smooth top grain leather, oiled feel medium-firm
temper.
Oil tanned leather

Oil tanned leather

Rose-tanned leather
Rose-tanned leather is a variation of vegetable oil tanning and brain
tanning, where pure rose otto replaces the vegetable oil and emulsified
oils. Rose-tanned leather tanned leaves a powerful rose fragrance even
years from when it is manufactured. It has been called the most valuable
leather on earth, but this is mostly due to the high cost of rose otto and its
labor-intensive tanning process.

Rose-tanned leather

Synthetic-tanned leather
Synthetic-tanned leather is tanned using aromatic polymers such as
the Novolac or Neradol types (syntans, contraction for synthetic tannins).
This leather is white in color and was invented when vegetable tannins
were in short supply during the Second World War. Melamine and other
amino-functional resins fall into this category, as well, and they provide the
filling that modern leathers often require. Urea-formaldehyde resins were
also used in this tanning method before people realized the hazards that
formaldehyde presents to tanners and consumers.

Alum-tanned leather
Alum-tanned leather is transformed using aluminium salts mixed with a
variety of binders and protein sources, such as flour and egg yolk. Alum-
tanned leather is technically not tanned, as tannic acid is not used, and the
resulting material reverts to rawhide if soaked in water long enough to
remove the alum salts.

Alum-tanned leather

Fur tanned leather
Simply omit the dehairing process and move to the next step. The
tanning process breaks down the glycerin and loosens the fibers of the
skin. The agent used in this method is found in the brain of the animal
that provided the hide/fur.

Fur tanned leather

Raw leather
Raw leather is made by scraping the skin thin, soaking it in lime, and then
stretching it while it dries. Like alum-tanning, rawhide is not technically
"leather", but is usually lumped in with the other forms. Rawhide is stiffer
and more brittle than other forms of leather; it is primarily found in uses
such as drum heads and parchment where it does not need to flex
significantly; it is also cut up into cords for use in lacing or stitching and
for making many varieties of dog chews.

Raw leather

According to surface finish
• Aniline
• Semi aniline
• Pu coated
• Pigmented
• Patent

Aniline leather
Aniline leather (pure aniline) is dyed with aniline dye. This type of dye is
transparent (translucent) like wood stain. You can therefore see the
structure of the skin where the animal has had wrinkles and creases. Insect
bites, boils, cuts and wounds can also be seen quite clearly, as you can see
the knots and veins in a piece of stained wood.

For pure aniline is used only the very best hides, those who have the fewest
or least severe blemishes, i.e. that only a small proportion of the total
production of leather skin can be used for aniline leather.
Pure aniline has basically no surface protection, either in the form of finish
coating or topcoat / finishes, and you will with a magnifier be able to
clearly see the hair follicles.
Aniline leather

One sees that they are fully open and not filled or half-filled. However,
aniline leather is often factory treated with special wax to give it some
protection and a comfortable feel to the touch.
Characteristics: The leather structures and blemishes can be seen quite
clearly. Hair follicles are fully open. Very
absorbent. Very soft. Very sensitive to light.
Aniline leather

Aniline leather

Semi-aniline
Semi-aniline is aniline leather with one or more types of surface protection,
which makes the leather more resistant to moisture, dirt and stains than pure
aniline leather.
Some qualities have a slight pigmentation (color) on the surface before they
are applied surface protection. This pigmentation are often made slightly
iridescent to resemble the structure of aniline leather.

The surface protection can be from almost nothing to quite a lot. However, one
must assume that manufacturers are trying to get as thin and soft a surface as
possible to come closer to the comfort of the pure aniline leather.
There are and continues to be developed so many new types of leather and
combinations that they are impossible to classify further.
Characteristics: The leather structure can be seen or sensed. You sense a form
of surface protection. With a magnifying glass the hair follicles are clearly seen
with more or less filling. Can be slightly water-resistant. Quite soft to relatively
soft. Different, but overall high sensitivity to light.
Semi-aniline

Semi-aniline

Pu coated finish
The material is coated by applying a surface layer of a chemical such as
polyurethane to the grain side of the leather.
The advantages of coated leather are that it is much cheaper than genuine
leather and has a consistent surface finish. However, coated leather doesn't
look or feel like genuine leather and is nonporous, meaning the material
doesn't breathe. Coated leather is much stiffer and less flexible than
genuine leather and is much more likely to crack in hot and dry conditions.

Pu coated finish

Pigmented Leather
Pigmented leather needs one or more topical coatings for two reasons: to
improve the durability and to make the colour more even. The outside face
of the hide is coated with a pigmented resin, and then a subsequent clear-
coating(for durability). These resins create a film that bonds to the surface
of the leather. It's primary goal is to protect the leather, providing wear,
stain, and fade resistance. And this leather is called 'Pigmented
Leather' or 'Finished Leather'.

Characteristics: The leather structures and blemishes are not seen. The
leather has a thick surface protection in the form of solid-color
and finishing agent. Hair follicles is seen or sensed with a magnifying
glass, but has a distinctfilling (they do not have to
be completely filled). Good water resistance. Can be relatively soft, but
not to the same extent as aniline. Most qualities have good light
fastness, but the light fastness also depends on the individual color.
Pigmented Leather

Pigmented Leather

Patent leather
Patent leather is a type of coated leather that has a very glossy, shiny finish. The
coating process was introduced to the United States and improved by inventor Seth
Boyden of Newark, New Jersey in 1818, with commercial manufacture beginning
September 20, 1819. Boyden's process, which he did not patent, used a linseed oil–
based lacquer coating. Modern patent leather usually has a plastic coating.
The finish of patent leather shoes is very robust and, generally, does not require
much cleaning. However, after time, the gloss of one’s shiny patent leather shoes
can begin to fade.

Patent leather

Some other types of leather
• Kid leather
• Napa leather
• Chamois leather
• Glazed
• Embossed
• Butt leather
• Bonded leather
• Bycast leather
• Russia leather
• Boiled leather
• Corinthian leather
• Morocco leather
• Composition leather

Kidskin/kid leather
Kidskin or kid leather is a type of soft, thin leather that is traditionally
used for gloves (hence the phrase 'kid gloves,' used since at least 1888 as a
metaphor for careful handling). It is widely used for other fashion
purposes such as footwear and clothing. Kidskin is traditionally made
from goatskin - more specifically, the skin of young goats (or 'kids'),
although equivalent leathers such as lambskin and chicken skin (actually a
form of calfskin) give the same effect.

Kidskin/kid leather

Napa leather
Napa leather is a leather, typically dyed, made from kid, cow, calf, lamb or
other skin by tanning. It is noted for its soft temper. It is a generic term in
the leather field and has no distinct test for characterization. Because of this
ambiguity, the term is often used in advertising to imply that a leather has a
soft hand. Among other uses, Napa leather is often used in leather products
such as furniture, clothing, handbags, and shoes. As the term is used today,
Napa Leather may be either natural grain, or more likely, corrected grain.

Napa leather

Chamois leather
Chamois leather also falls into the category of aldehyde tanning, and like
brain tanning, produces a porous and highly water-absorbent leather.
Chamois leather is made using marine oils (traditionally cod oil) that oxidize
easily to produce the aldehydes that tan the leather to color it.

Chamois leather

Embossed leather
Embossed leather gives a creative & decorative look to leather by
stamping a pattern onto the leather.

Glazed leather
Glazed leather is simply leather that has been burnished or polished to make it
appear shiny. After burnishing, the leather's surface appears to have a glossy
finish. Sometimes a soluble dye is added to create an aniline glazed finish. Heat
caused by friction -- rubbing -- is what creates the glaze.
After the burnishing compound on the leather has dried, leather manufacturers
shine up the surface of leather using a glazing jack, glazing machine or leather
polisher that has a wood or glass cylinder on it.

The arm moves back and forth while the leather is sandwiched between the
roller and a belted material underneath. Controls can adjust the pressure of
the roller as needed. As the wood or glass cylinder compresses and rolls
against the surface of leather, it creates a glazed finish. You can also do this
by hand on your leather-crafted items.
Glazed leather

Glazed leather

Butt leather
Butt leather is vegetable tanned leather. utt leather is the leather type most
commonly used for equipment such as saddles, harnesses, bags, cases and
the like. It can be tanned with very different tannins. Both bark , seeds,
leaves and roots are used from various plants and trees, for example. oaks.
Butt leather usually have no real surface protection, and is therefore
extremely susceptible to spills and sticky fingers.

Butt leather is expensive to manufacture; the tannins are expensive and the
process is slow.
Butt leather can be pressed into shape. When it is wet, one can
easily press it in to shapes of, for example, knife sheaths, revolver
casings etc. One can also stamp characters and letters in the leather, while
it is wet.
Butt leather

Characteristics: The structures and blemishes of the leather are clearly
visible. The surface seems natural/untreated. Hair follicles are clearly
visible and open. Strongly absorbent. The color whitish/ yellowish can
be sensed even when the leather is dyed with other colors. The thickness
of this leather can far exceed the thickness of chromium
tanned leather (common furniture leather).Somewhat sensitive to
light but slightly less sensitive than aniline.
Butt leather

Butt leather

Bycast/Bicast leather
Bycast leather is a split leather with a layer of polyurethane laminated to the
surface and then embossed. Bycast was originally made for the shoe industry, and
later adopted by the furniture industry. The original formula created by Bayer was
strong but expensive. The result is a material that is slightly stiffer but cheaper
than top-grain leather but has a much more consistent texture. Because its surface
is completely covered in plastic, is easier to clean and maintain, but is not easily
repaired. When used for footwear, it cannot be considered equal to conventional
leather as it lacks the strength, breatheability, and durability of the natural product.

Bicast leather

Bonded leather
Bonded leather, also called reconstituted leather or blended leather, is a
term used for a manufactured upholstery material which contains animal
hide. It is made as a layered structure of a fiber or paper backer, a pulp
made from shredded leather, and a polyurethane coating which is embossed
with a leather-like texture. Bonded leather is made by shredding leather
scraps and leather fiber, then mixing it with bonding materials. The mixture
is next extruded onto a fiber cloth, or paper backing, and the surface is
usually embossed with a leather-like texture or grain.

Color and patterning, if any, are a surface treatment that does not penetrate
like a dyeing process would. The natural leather fiber content of bonded
leather varies. The manufacturing process is somewhat similar to
the production of paper. Applications: Bonded leather can be found in
furniture, bookbinding, and various fashion accessories. Products that are
commonly constructed with different varieties of bonded leather include
book covers, cases and covers for personal electronics, shoe components,
textile and accessory linings, portfolios and briefcases, handbags, belts,
chairs, and sofas.
Bonded leather

A more fragile paper-backed bonded leather is typically used to cover books
such as diaries and Bibles, and various types of desk accessories. These
bonded leathers might contain a smaller proportion of leather than those
used in the furniture industry, and have some leather exposed in the
product's surface, producing the characteristic odor associated with leather.
Bonded leather

Bonded leather

Russia leather
Russia leather is a particular form of bark-tanned cow leather. It is
distinguished by a later processing step, after tanning, where birch oil is worked
into the rear face of the leather. This gives a leather that is particularly hard-
wearing, flexible and resistant to water. The oil impregnation also deterred insect
attack. The high quality of this leather, its usefulness for a range of purposes, and
its manufacture being difficult to replicate elsewhere, led to it being a
major export good from Russia in the 17th and 18th centuries. It was an
important item of trade for the Muscovy Company.

Russia leather

Boiled leather
Boiled leather, sometimes called cuir bouilli, was a historical construction
material for armour. It consists of thick leather, boiled in water. According
to some sources, boiled oil and wax were used as well, while others posit
the use of ammonia from fermented animal urine. The boiling causes the
leather to become harder but also more brittle. The leather remains flexible
for a short time after boiling, allowing it to be molded into larger plates.

Boiled leather

Composition leather
Composition leather is made from recycled leather off-cuts, trimmings
and shavings that would normally be sent by the leather industry
to landfill. The type of leather specifically used in the manufacture of
composition leather is called ‘wet blue’. This raw material, which is
duck-egg blue in colour (hence the name), comes straight
from tanning.The shavings are bonded to a fabric layer commonly using
a process such a hydro-entanglement to force the leather dust into the
fabric layer.

The product is then finished, typically with a polyurethane based system to give a
resemblance of leather. The amount of leather shavings within the final product
typically constitute less than 50% of the product.
Composition leather claims to enable a higher cutting yield than leather. This is
because the material is man-made from leather fibres, produced in rolls 1.4 m wide
and is not derived from leather hides, as in traditional leather. However, composition
leather has stretch characteristics along its warp and weft which it inherits from its
fabric substrate. Consequently, it stretches more in one orientation than the other.
When orientation is considered, the yield of composition leather is comparable or
worse than real leather.
Composition leather

Composition leather is increasingly being adopted as an alternative to traditional
leather for footwear, leather goods (including document folders, bags and
wallets), airline seating, taxi seating, car upholstery, marine upholstery,
commercial upholstery and domestic upholstery.
It must be remembered that composition leather is not genuine leather and cannot
legally be marketed or suggested to be the same as leather. The method of
manufacture of composition leather is similar to bicast leather and has similar
problems with delamination and poor aesthetic qualities associated with plastic or
synthetic leather.
Composition leather

The unique properties of skin which are transmogrified into leather (breathability,
strength, elasticity, retention, flexibility, softness, durability) are the result of the
interwoven helix created by collagen fibres. These elongated fibrils give leather
its unique characteristics and fundamental attributes.
If you grind these fibres into a powder (as practiced in composition leather) you
lose all of the natural characteristics and attributes of leather. It can be argued
that composition leather whilst having some matter that originated in skin, does
not exhibit any of the useful properties of leather that gives it its unique qualities.
Composition leather

Composition leather is also known to have poor heat gunning properties,
in that it does not shrink. When heat is applied to the surface, it typically
absorbs heat until it burns unlike leather which can be shrunk to fit. Heat
gunning is commonly used finishing technique in upholstery.
Composition leather

Composition leather

Corinthian leather
Corinthian leather is a term coined by the advertising agency Bozell to describe the
upholstery used in certain Chrysler luxury vehicles. The term first appeared in
advertising in 1974.Although the term suggests that the product has a relationship to or
origination from Corinth, there is no relationship; the term is merely
a marketing concept.
While the term was first used during the marketing campaign for the 1974 Imperial
LeBaron, it is usually associated with the marketing campaign for the 1975 Cordoba and
that campaign's celebrity spokesperson, Ricardo Montalban, who described "the thickly-
cushioned luxury of seats available even in soft Corinthian leather".

Despite the exotic origin suggested by the name "Corinthian leather", much of the
leather used in Chrysler vehicles during the era originated from a supplier located
outside Newark, New Jersey.
Some sources say the term refers to the combination of leather seating surfaces and
vinyl seat sides. However, most cars worldwide with "leather upholstery" have
matching color vinyl seat bases and often the rear faces of the front seats, the head rests,
and the door facings. The standard term in period car catalogs was "leather with vinyl",
and sometimes "leather seat facings". When Montalban was asked by David
Letterman on Late Night with David Letterman what the term meant, the actor playfully
admitted that the term meant nothing.
Corinthian leather

Corinthian leather

Morocco leather
Morocco leather (also Levant Morocco or the French Maroquin, or
German Saffian from Safi a Moroccan town famous for leather, or from Middle
Persian Saxtag Modern Persian) is a soft, pliable form of leather widely used for
gloves and the uppers of ladies' shoes and men's low cut shoes, but traditionally
associated with book bindings, wallets, linings for fine luggage, and the like.
The finest grades of Morocco leather are goat skin, but by the late 19th century
other skins often were substituted in practice, particularly sheep skin and split
calf skins.

For example, French Morocco, is a variety made of
sheepskin. The tanning process varied widely, but the traditional tanning
material was sumac.
The traditional tanning process was skilled and elaborate; according to the
application, the preparation either would aim for a carefully smoothed finish, or
would bring up the grain in various patterns such as straight-grained, pebble-
grained, or in particular, in a bird's-eye pattern. Morocco leather is practically
always dyed, traditionally most often red or black, but green, brown or other
colors also were available, and in modern times there is no special constraint on
color.
Morocco leather

Morocco leather

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Presented by:
S. M. Murshidur Rahman
Department of Leather Engineering,
Khulna University of Engineering & Technology (KUET), Khulna-9203, Bangladesh.
Email: murshidurkhulnabd@gmail.com
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