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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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