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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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