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Education Booklet
AHFA Leather
Education Booklet
Purpose Statement
The purpose of the
AHFA
Leather Education
Booklet is to publish information that assists retail
leather customers in making informed buying
decisions, and that equips the retail sales
associate / marketing specialist with overall leather
knowledge and education in order to correctly sell
upholstered leather furniture.
Published December 2004
Table of Contents
1. Leather History
2. Leather Tanning Process
3. Understanding Natural Markings of Leather
5. Advantages of Buying Leather
6. Leather Types
7. Type of Leather that Best Suits My Lifestyle
8. Leather Care Tips
9. Glossary of Terms
10. Disclaimer
11. Credits
1. Leather History
The raw skins of animals were first used by primitive man to
protect their bodies from severe
weather, cold winds and rain during the ice age some 500,000
years ago. It was not until centuries
later that man began to stretch out the skins and dry them under
the sun to keep them from
rotting. Some of the fluids from the animals were rubbed into
the pores of the skins to soften the
hides and make them more comfortable against human skin. It was
discovered much later that
parts of some trees contained an acid-like substance called
tannin (or tannic acid), which could
convert raw hides and skins into what we know as leather.
The bark of oak trees was the main material used. Some countries
did not have oak trees so
vegetable tanning materials like sumach leaves and other plant
leaves were used. If the raw material
was extremely thick, hides were soaked in the tanning liquid for
as long as two years.
Once the tanning process was discovered, people began using
leather for such things as footwear,
clothing, saddles, holsters, bags, bindings, buttons, and many
other things.
During the time of the industrial revolution, innovation and
travel brought huge new opportunities
for the makers of leather. Horse drawn carriages, luggage,
trunks, upholstery and fashion all became
important consumers of leather.
Nearly a century later, furniture design in the 1950s required
softer, more pliable leathers for
seating. This was accomplished by incorporating chromium salts
in the tanning process.
Today, the leather industry continues to improve its methods and
processes through aggressive
technology but with an additional emphasis on protecting our
natural environment. Similarly, with
very few exceptions, animal hides are a by-product of the meat
industry; almost all leatherproducing
animals in just about every country are reared for the food they
provide, not for their
hides.
Leather tanning has come a long way from its primitive
beginning. Early leathers were made primarily
from ordinary cowhides, calfskins, pigskins, deerskins, and
goatskins. However, today’s
fashion-driven furniture, apparel, and clothing industries
incorporate many exotic skins such as
alligator, crocodile, and lizard, as well.
In a world of man-made materials, natural, elegant leather
continues to command interest and
appeal. Nothing says quality, fashion and style like leather.
2. Leather’s Tanning Process
What is Tanning?
A
process that uses tanning agents to convert a raw hide into a stable,
nonperishable
material. This is achieved by cleaning, drying, and preserving
the hide. (See below
for a more detailed look at the tanning process.)
Curing – The leather hide is cured by immersion in a salt
solution to protect it from deterioration
and to preserve it for future use.
Soaking – The leather hide is soaked in water to remove the salt
solution and re-hydrate the hide
to its original flaccid condition.
De-hairing – The soaked hides are treated with a lime solution
for the de-hairing process. The
lime solution not only removes the hair, but also fats and
soluble proteins.
Tanning – Tanning involves drumming the hides in a mixture of
chemicals. Two of the most common
types of tanning include chromium tanning, which results in a
wet blue appearance, and
vegetable tanning.
Splitting – The average thickness of a cowhide is 5mm before
splitting. The hides are split in a
splitting machine which activates a fast running wirecutter.
This operation divides the hide into
two pieces: top grain leather and split leather. The top grain
hides are then shaved on the flesh
side to create a uniform thickness. Standard top grain
upholstery leather thickness can be
0.9mm-1.4mm. Split leathers are typically used on non-stress
areas, such as outside backs and
outside arms.
Sorting – The hides are then sorted or separated by differing
levels of quality. This quality is
based on the extent of natural markings which could include tick
bites, brands, barbed wire scars,
and/or stretch marks. This process is called selection. The
highest quality of leather hides are
normally termed “A” selection. “B” and “C” hides possess a
higher number of natural markings,
therefore reducing overall selection.
Dyeing – The leather hide is drum dyed. The dye concentration in
the drum affects level of penetration
into the hide, richness of shade, colorfastness to light, ease
of dry cleaning, and resistance
to rubbing. The dyed leather is then treated with fat-liquors
for softness and strength.
Drying – After the dyeing process, the leather hide can retain
45-60% water. Most upholstery
leather is tunnel dried where the temperature and humidity are
controlled. After the leather is
dried, it dries to a paler shade as the oils spread uniformly
and the dyes penetrate deeply.
Finishing – The finishing of a leather hide involves both
mechanical and chemical treatments.
The hide is first trimmed and conditioned with fat-liquors to
obtain uniform moisture content. The
hide is then softened with a massage machine and stretched. Some
leathers are further processed
by applying a top coat finish to the grain surface. The top coat
adheres to the leather’s
surface while increasing the resistance to abrasion, cracking,
peeling, rubbing, light, and heat. A
pigmented finish is sometimes applied which contains a variety
of colorations, resins, lacquers,
oils and/or waxes. Afterwards, the hide is milled in a dry drum
to soften the leather. Note:
leather can be finished a variety of ways depending on quality
of hide, type of leather, and level of
pigmentation.
Graining
– The grain, similar to human fingerprints, is
unique to
each individual hide. It is the hallmark of full grain leather
hides
and can vary from hide to hide or even within one particular
hide.
3. Understanding the Natural
Markings of Leather
Branding Marks
– Brand
marks, or fire brands, are used as
identification marks and are part of virtually every hide.
Stretch Marks
– Stretch marks occur as a result of giving
birth
and become a permanent marking on the cow.
Healed Scars
– Scratch marks are the result of the cow’s
unsheltered
life and evidence that the hide is indeed top grain. Hides with
fewer
scratch marks are usually more expensive, but the marks do not
affect
strength or durability. Typical healed scars include those
caused by
insect/tick bites and barbed wire marks.
Insect/Tick Bites
– Scars caused by the abundance of insect
and/or
tick bites. Typically, these scars heal but leave visible
markings.
Fat Wrinkles
– Wrinkles occur naturally in the loose skin
around
the neck and belly of all cows. The skin must be loose to allow
the
needed flexibility for grazing and overall growth.
Backbone
– Natural furrows appear along the backbone of all
hides due to the animal’s physiology.
Leather – An “Economical Choice”
– Most customers are
unaware that leather
provides an economical approach to buying upholstered furniture.
There are many
types and styles of leathers that range in price. This allows
each customer to experience
the pleasure of owning leather furniture by offering affordable
yet varying
price ranges for all pocketbooks.
5. Advantages of Buying Leather
COMFORT
Leather is a natural material.
Leather is a lot like our skin – porous.
Leather “breathes” by absorbing up to 15% of its own weight in
humidity/water. It
absorbs and releases moisture that never stays on the surface
enabling it to adjust to
our body temperature.
Leather has excellent temperature adaptation making it
comfortable during the heat of
the summer and cool of the winter.
CONFORMABILITY
Leather molds to a form, but will not stretch out of shape.
Leather conforms to your body shape and becomes more comfortable
with use.
Only leather ages so that it becomes more supple throughout the
years.
UNIQUENESS
Each leather hide is unique – No one hide is exactly like
another.
Leather comes with its own distinctive markings and
characteristics making each
purchase truly unique.
DURABILITY
Leather has legendary tear strength making it one of the
strongest upholstery
materials known to man.
Leather’s strength and elasticity gives it high ripping
resistance.
FLAME RESISTANCE
Leather is naturally flame resistant and will not readily burn
or melt.
CLEANABILITY
When properly maintained, leather is easy to clean.
Like our skin, leather has tight as well as strong fibers that
prevent the penetration of
dust, lint, animal hairs, or cigarette smoke.
Leather is an ideal choice for those persons who are
dust-sensitive or possess
allergenic conditions.
6. LEATHER TYPES
Basic Leather Classifications
Type A – Aniline
Crust leather that has received only aniline dyes for color,
then dried,
softened and milled.
No protective finish.
Shades may vary from hide to hide and within a single hide.
Requires a high degree of preventative maintenance.
Susceptible to surface scratches.
Absorbent
May have special effects such as, but not limited, to wax, oil,
etc.
Type P – Protected
Crust leather that has received additional aniline dyes,
pigmentation for
color consistency, and/or a protective top coat finish, then
dried, softened
and milled.
May be partially or fully corrected.
Requires a low degree of preventative maintenance.
Surface is more difficult to scratch.
Least absorbent.
May have special effects, such as, but not limited to, hand
antiquing, savauge, etc.
Type N – Nubuck
Crust leather that has received only aniline dyes for color,
then dried, softened,
sanded or buffed, and milled.
Surface has a visible nap.
Shades may vary from hide to hide and within a single hide.
Requires a high degree of preventative maintenance.
Susceptible to surface scratches.
May have special effects, such as, but not limited, to wax, oil,
etc.
7. Type of Leather that Best Suits My Lifestyle
8. Leather Care Tips for ALL Leather Types
Avoid placing your furniture in direct sunlight (under windows
or skylights). All
materials will fade over time when placed in direct sunlight.
Some leathers are
especially sensitive to sunlight.
Maintain at least two feet between your furniture and heating
sources. Prolonged
exposure to heat vents and radiators will cause your leather to
dry out.
Like all items in your house, leather can accumulate dust. You
can fully remove dust
particles from the surface with a soft cloth, making it ideal
for dust sensitive persons.
Certain types of leathers perform better when preventative
maintenance is practiced.
Your retailer may offer additional Leather Care and Maintenance
suggestions or
products.
Use of general household cleaning products, chemicals and
abrasives are not
recommended as they can break down the leather’s protective
surface and cause
damage. Never use harsh chemicals or cleaning agents (such as
furniture polish,
ammonia, or detergent soaps) on your leather furniture. Avoid
all products containing
solvents, silicones, or oils, as they may negatively affect the
leather’s surface.
9. Glossary of Terms
Absorption –
The ability to
take on moisture while experiencing a physical change.
Aniline Dyed
–
Leather that has been dyed throughout by immersion
in a dye-bath and has not received
any coating of pigmented finish. This form of transparent dye
penetrates the hide with color.
Bi-cast –
Application of
polyurethane surface coating on a split or top grain
leather.
Buffing
–
Leather which has been smoothed by mechanical
abrasion to minimize surface blemishes,
such as healed scars. This technique obliterates much of the
natural grain, therefore the leather is
normally embossed to flatten or create a grain-like appearance
as much as possible.
Chromium Tanning
–
Upholstery leather which has been tanned with
chromium salts. This
method makes the hide flexible and supple .
Corrected Grain Leather
–
Leather from which the grain layer has been
partially removed by
buffing and upon which a new surface has been created by various
finishes (e.g. embossing).
Crocking
–
The rubbing off of surface substances or color onto
another material. Commonly referred
to as dye transfer.
Crust
–
Leather
that has been
tanned, dyed, and dried – but not finished.
Distressed –
Process
used to create an effect resembling a worn look or an aged
appearance.
Techniques used to create this effect include tumbling the hides
with abrasive items in order to
scratch the leather’s surface.
Drum Dyed
–
Leather is immersed in a drum with dyes and tumbled
to insure complete color absorption.
Embossing
–
Process of printing leather with a raised pattern
either imitating or resembling an animal
grain pattern. A unique pattern may be embossed on the leather
that is unrelated to the natural
grain pattern. Leathers are pressed with an embossing plate
under heat and pressure to either lay out
the grain as smoothly as possible or to impart a textured
effect. Embossing may also be done to disguise
defects or blemishes.
Fat Liquoring
–
Process of replacing oils that have been depleted
from the hide during the tanning
process .
Fat Wrinkle
–
Natural wrinkles in the leather’s grain that are
unique to each hide. Normally visible
only in full grain leathers. Common around the neck and shoulder
areas of the hide.
Finishing
–
Any process performed after the initial dyeing stage
such as buffing, embossing,
milling, spraying, etc. These leathers are treated with a
topcoat substance to help provide
abrasion and stain resistance. These substances can be lacquers,
varnishes, polymers, or
enamels. The finishing substance may also include additional
pigments and/or dyes.
Full Grain
–
Leather which has not been buffed or abraded
retaining all natural markings
and characteristics.
Glazed
–
Leather treated with a pigment containing not only
gloss, but also protection.
Gloss Finish –
Higher
shine/sheen level finish usually with enhanced texture
added.
Grain
–
Pattern characterized by the pores and peculiar to
the animal concerned, visible on
the outer surface of a hide after the hair has been removed.
Hand
–
Term describing the leather’s degree of softness and
feel as well as the reaction of
the sense of touch when leather is held in the hand.
Hand Antiqued
–
Hand application of a darker color over a lighter
color creating a dramatic
highlight.
Hide
–
The whole or entire skin of a larger animal, usually
cattle, for upholstery leather.
Leather
–
A hide or skin that has been tanned into a
non-perishable material.
Matte Finish
–
Low gloss finish usually with enhanced texture added.
Micropigment –
Coloring
of the hide by using a coating which contains clear,
transparent
pigments. This coating can also be accompanied by a thin layer
of opaque pigmentation
creating a more uniform shade.
Milling/Tumbling
–
Process in which tanned hides are placed in drums
with heat and water
and tumbled to create a desired softness or effect .
Naked Leather
–
Tanned, aniline dyed leather that has no protective
top coat. Commonly
referred to as pure aniline.
Nap / Pile –
A “suede like”
effect achieved by buffing to raise the natural
fibers of the leather’s
surface.
Natural Grain
–
Leather whose grain has not been altered in any way.
The natural appearance
of the grain is predominant showing visibly healed scars, fat
wrinkles, insect bites, etc.
Nubuck
–
Top grain, aniline dyed leather that has been buffed
to create a “suede like” nap
effect.
Patina
–
Surface luster that
develops on Pure Aniline Leathers and Nubuck
Leathers
which grows more beautiful with use and the passing of time.
Pigment Finish
–
Coloring of the hide by using a coating which
contains pigments and
other opaque materials. This finish creates a more uniform shade
and an increased resistance
to fading.
Pull-Up
–
Leather that derives its look and some colorations
from dyes and oils. When the
leather is pulled during upholstering, the oils in the leather
cause the color to migrate and become
lighter. Pull-ups are dominated by either waxes or oils, or a
combination of both.
Pure Aniline
–
Leather that is aniline dyed and exhibits natural
markings and characteristics
because the grain has not been altered in any way.
Sauvage / Kela
–
Two-toned effect in which a darker color is applied
over a lighter color.
This effect can be created during the finishing process either
with a roller or spray equipment,
or by hand. Similar to faux finishes on walls.
Semi-Aniline
–
Leather that has been aniline dyed throughout then
protected by a clear or
pigmented finish coating thus creating a more consistent color
than pure aniline leathers.
Natural markings may be visible with semi-aniline leathers.
Split Grain
–
The underneath layer of a hide which has been
“split” off when the top grain is
separated. If finished, the split is heavily embossed and
surfaced treated.
Suede –
Leather
produced from the underneath layer/lower split of a hide
possessing a
velvet-like nap effect. Suedes do not have the same durable
characteristics as top grain leathers.
Tanning
–
Process using tanning agents to convert a raw hide
into a stable, non-perishable
material. Tanning strips the hide of indigenous color making it
receptive to color dyes.
Top Grain
–
Top part of the skin or hide. The grain may be
either Full Grain or Embossed
Grain. The Top Grain of the hide is stronger and more flexible.
Vegetable Tanning –
Leather
which has been processed by using tannins obtained from bark,
wood, or other parts of plants and trees. Although this tanning
process adds to the toughness
of leather, it also limits the stretching of the leather.
Vegetable tanned leathers are used more
commonly manufacturing shoes, bridles, handbags, etc.
Wet Blue –
Refers to the
“blue” color and appearance created by the chromium tanning
process.
10. Disclaimer
The contents of this booklet have been compiled from the
contributions
of leather suppliers, leather upholstery manufacturers,
furniture
retailers, and industry consultants.
All materials submitted have been carefully edited and placed in
a
format designed to establish “standards” that can easily be
recognized
by all segments of the leather industry.
Acceptance and practice of the enclosed information is entirely
at the
discretion of the reader.
The American Home Furnishings Alliance (AHFA) has supported and
approved the development and publishing of this collection of
industry
information .
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