Leather
Upholstery
Fine leather upholstery used to be found in the dens and living rooms
of only the very wealthy. The category was characterized by heavy, traditional
styles and the use of strong colors such as burgundy, oxblood, burnt orange,
rust, walnut, tortoise, navy and blackberry. These leathers generally had
heavily glazed, shiny finishes. Massive, traditional chesterfields, tufted
wing chairs, traditional saddlearm and double bustle pub sofas characterized
leather upholstered furniture styles.
Today, due to advances in tanning technology and style innovations,
sales of furniture upholstered with leather covers has grown at tremendous
pace.
Contemporary styled leather upholstery has emerged as a strong
selling category with broad consumer appeal. Not only has the styling of
upholstered pieces changed, the leather used to cover contemporary pieces,
now comes in a wide variety of designer colors and is generally soft, pliable
and comfortable. The way leather is applied to frames has also changed.
Leather is now gathered, pleated and draped in much the same way as fabric
covers.
Leather
History
Like stone, wood and wool, leather is a natural product. It
has been a prized commodity throughout history. All of the earlier Renaissance
styles, particularly the Spanish and English favored leather upholstery.
Techniques for embossing, tooling, painting and gilding leather were disseminated
by Spanish craftsmen in the 16th and 17th centuries. Throughout this period,
all types of furniture were covered with leather and studded with decorative
nail-head patterns. In the 18th century, the art of preserving hides and
tanning them into leather had become an old, respected trade. The tanning
process took almost a year and was completed by coating the hides with
oil and grease, then scraping and treading on them. Oxhide and calf skins
were a favorite in the late Louis XIV styles and fine goat leather was
often used by Chippendale and subsequent designers. Then, as today, cattle
hides were the major leather source because of their availability, strength
and hide size.
Features
and Benefits
Leather has properties which make it superior to other upholstery
materials. Consider the following:
Leather outlasts fabric covering, having an exceptionally long useful
life, usually 4 to 5 times longer than fabric.
It will not tear and is 4 to 5 times as strong as other upholstery materials
-- even along the seam lines.
Colors are absorbed by the leather and will not rub off.
It is fire resistant and emits no toxic fumes, even when exposed to
intense heat.
Modern leather does not crack or peel. It stretches and retains its
shape without sagging.
It "breathes", assumes body temperature rapidly and is instantaneously
comfortable.
It resists heat and sun damage.
Leather is a practical material, ideal for busy lifestyles. No special
solvents or cleaners and no lengthy or expensive procedures are necessary
for its care.
Leather ages well. It will not wear like fabric covers. Instead, fine
leather acquires a "patina" and may become more supple with age.
Quality
Leather
Leather is made from animal hides that are converted through a many
step process which preserves, softens, beautifies and protects the finished
product. Only a small percentage of hides are used to remake upholstery
leathers which must have large sections that are free from serious blemishes.
Whereas it takes only a small piece of leather to make a good shoe... a
sofa cushion requires a large panel of high quality.
It is important to understand the differences between the basic
types of upholstery leathers, because the kind of leather used on an upholstered
piece greatly affects its cost, wearability and beauty. Although this terminology
many seem confusing at first, it is actually very straightforward.
As part of the involved upholstery leather preparation process, suitable
animal hides are split into a top layer (the one which had hair on it)
and a thick lower layer. The top layer, also called top grain, can either
be processed into full grain leather which is not buffed and sanded; or
into corrected grain leather that has had the surface markings altered
by buffing and sanding.
Generally, leather that has too many surface imperfections (too much
character) will require correction. Full grain leather, is considered to
be of greater beauty and higher quality than corrected grain leather, and
so commands a higher price.
The lower layer may then be further split and processed into
suede split or coated split leather. Coated split leather is somewhat stiffer
and less durable than top grain leather. It is sometimes used to cover
upholstered sides and backs that do not need to flex and move much.
Consumer
Expectations
Many American consumers expect leather to be flawless; to look
and wear like vinyl, but to feel soft and supple. This view is largely
inconsistent with the reality of leather. Even the best quality leather
has flaws and natural markings. These subtle markings on the top grain
layer are analogous to fingerprints. They distinguish genuine leather from
man-made matertals.
Grain Correction
The reason why some top grain leather is corrected, is to minimize
the appearance of the gross surface imperfections which many consumers
find objectionable. This buffing/sanding process makes the leather more
uniform. Natural looking patterned effects can be re-introduced by coating
the leather with layers of pigment finish and embossing it under heat or
high pressure. This process can smooth the grain or produce unique patterned
effects (ostrich, alligator, lizard, etc.).
Tanning
Tanning is the process that turns an animal hide into leather.
It preserves the hide, makes it softer, more pliable and durable. Virtually
all of the leather produced today has been tanned with a chromium tanning
process which is a type of mineral tanning.
You may remember leather, that after several decades of use
cracked, eventually revealing reddish, rotted leather underneath the pigmented
finish. This leather was most likely vegetable tanned.
Actually, the durability of chrome tanned and vegetable tnned
leather is comparable, however, chrome tanned leather is less susceptible
to this problem of red rot. With normal use and care, modern chromium tanning
techniques produce leather upholstery that can last several decades.
Dyeing
and Finishing
Tanned leather is first colored with a penetrating dye. The dye permeates
the surface of the hide giving it color but not covering over natural markings.
The leather can then be finished in one or more coating operations, with
clear or pigmented finishes that do not penetrate the surface. These final
finishes provide abrasion and stain resistance as well as color enhancement.
Generally, the more surface finish a leather has, the stiffer (boardier)
it becomes, but tanning formula and hide quality also affect leather stiffness.
Aniline dye in common industry usage, refers to any clear dye
that penetrates into the leather, coloring it, but not coating its surface
with pigment. Virtually all upholstery leathers are initially treated with
a penetrating aniline dye which allows the natural grain to show through.
The amount of dye used in leather production, depends on the
extent to which the dye has penetrated the leather. The dyeing of leather
can be controlled by the manufacturer to either fully or partially penetrate
it. Leather that has been fully penetrated with dye is known as fully struck
through leather. If it has only been superficially dyed (only the flesh
and grain surfaces penetrated), it is called partially struck through.
For obvious reasons, leather whose cut edges will be exposed in the finished
upholstered piece must have the dye fully struck through, but normal wear
will not expose the interior of partially struck through leather.
Types of
Leather
The three most commonly available basic types of leather are
pure aniline, semi-aniline and protected aniline leather.
Pure aniline leather, sometimes called aniline leather, aniline
finish leather or premium select leather is a product that has a clear
protective coating but no applied pigmented surface coating (finish). This
is the best quality and most expensive leather. It is made from hides having
a minimum of natural markings which have not needed to be grain corrected,
embossed, or coated with pigment. This leather may receive a clear protective
coating, but not a pigmented coating. Natural characteristics of the hide
show through and the surface is soft and supple. Moderate color variations
are normal and these unpigmented leathers tend to develop a rich patina
with age. Only a small percentage of hides are good enough to be converted
into pure aniline leather.
Semi-aniline leather (aniline plus 1eather) has not as some
believe had less aniline dye used in its manufacture than leather described
simply, as aniline leather, pure aniline leather or aniline finished. The
term semi-aniline leather describes full grain leather which contains only
a small amount of surface coating (finish); a premium product which allows
most of the natural character of the leather to show through. It is, therefore,
misleading to describe a heavily finished or protected leather as being
semi-aniline dyed.
Care should be exercised in purchasing delicate semi-aniline
leathers for high traffic/high wear areas. If a light colored pigmented
finish should wear off through abrasion or vigorous cleaning, it may expose
a neutral or contrasting color back.
Protected aniline leather is less expensive and more common
than pure aniline or semi-aniline leather. Its coloration is more consistent
and because it has been coated with protective pigments, the leather's
natural markings are less noticeable. Protected leather is more heavily
pigmented than semi-aniline leather and is actually easier to clean than
pure aniline leather because surface pigments repel water and stains...
standing up well to heavy use.
Leather
Care
Cleaning: Part of the reason why consumers like leather is
because it is easy to care for. It is not, however, indestructible. In
general, the more heavily finished a leather surface is, the more resistant
it is to spills and stains. Untreated leather absorbs and is easily stained
by oils. It can also be harmed by abrasive cleaners, powdered products
and organic solvents. Soap and water is good for routine cleaning, but
many commercially available leather cleaners also work. The latter often
contain lubricating materials which are intended to keep leather supple.
Really dirty leather may require the use of a mild detergent solution or
professional cleaning, but care should be taken because some detergent
solutions may not be pH balanced or contain compounds that could harm the
leather. Always follow the manufacturer's cleaning instructions and test
any cleaner on an inconspicuous area first. It is also a good idea to damp
wipe rather than soak the leather with water.
Pets and Placement: Some pets love to chew on leather, urinate on
it and scratch it. Consumers who suspect that their pets may damage their
leather upholstery may want to invest in a protective finish, and avoid
especially delicate leather covers. Placement out of direct sunlight, or
near radiators which many dry out the leather is also recommended.
Normal Wear and Colorfastness: Consumers who anticipate that their
sofa will see heavy or consistent use and are worried about dirt, stains
and wear, might be well advised to purchase a sofa that is darker in color
and has a heavier finish coat. More heavily finished leathers will maintain
their original looks longer, but tend to be stiffer and show less natural
character. Since heavily pigmented finish coats are often used to cover
up less desirable leather, they will also tend to be used in less expensive
upholstery applications.
Although a deep gouge or scuff mark may expose the interior
of the leather and give a contrasting color if the leather is not fully
struck through, normal use will rarely if ever wear through the grain enamel
of the leather. If wear or abrasion exposes a contrasting color, this is
almost always due to the pigmented finish being a different color than
the aniline dyed leather crust. Sometimes this is done purposely to achieve
tonal effects. The most uniform color and wear will be achieved by leather
which has been dyed and finished in the same shade.
You can tell if the final pigmented finish coat is a different
color than the dyed leather by examining a leather sample or patch found
under the seat cushion. Just compare the pigmented surface color with the
color of the opposite suede side.
Some suggested methods of cleaning leather surfaces follow.
We suggest that any cleaning method is always tried in a hidden area first.
For spills: Wipe up excess liquid immediately with a clean
cloth or sponge. If necessary use clean lukewarm water and let the leather
air-dry.
For spots and stains: Apply a mild, non-detergent soap solution
with a clean, wet sponge. Rinse well and let air dry. Especially stubborn
dirt may require a detergent solution, but care should be taken.
For butter, oil or grease: Wipe the leather with a clean,
dry cloth and let the remainder of the oil dissipate into the leather.
Do not apply water or try to wash a grease spot.
Professional cleaning services: There are specialized services
that clean, condition, restore, repair and spot re-finish leather furniture
in consumers' homes on a regular basis. They say that this kind of routine
maintenance extends the useful life of leather upholstery; keeping it clean
and in top condition.
Repair of holes, cuts and burns: Although it seems unlikely;
holes, cuts and burns in leather surfaces, wear and fading CAN be repaired
to like-new condition by skilled leather craftsmen.
ANILINE FINISH: Also known as pure aniline leather, aniline finish
leather is full grain leather which has been soaked in aniline dye, but
does not have any subsequent pigrrrented finish coats applied. This dye
can either completely or partially penetrate the hide with color allowing
the natural grain to show through. Only the best hides which are relatively
free from gross surface imperfections can be made into aniline finish leather.
It is soft pliable and expensive.
ANTIQUED FINISH: Leather finish accomplished by hand rubbing
leather with a dark dye after a lighter base coat has dried creating dramatic
highlights in the finished product.
ATTACHED BACK PILLOW: A pillow treatment which cannot be removed
from the upholstered piece.
BARREL BACK: A chair or sofa with the arms and back forming
a continuous curve.
BATTING: An operation performed on a hide before tanning to
remove chemicals such as lime introduced in earlier hide preparation steps.
BOX EDGED: A square seat front, with either welting or a sewn
seam on the top and bottom.
BRAND: A simple easily recognized pattern made by burning the cattle's
skin with a hot iron. Used for identification purposes, brands are normally
cut out of the hides and do not appear on finished furniture.
BUFFING: Hides are often buffed with an abrasive wheel to minimize
the appearance of gross surface imperfections such as wrinkles, parasitic
damage or healed scratches in the finished product. This process makes
leather more uniform, but also obliterates the natural grain and markings
that makes each hide unique and naturally beautiful.
BUTTON TUFTED: Buttons sewn through an upholstered surface
and tied down. The placement of buttons and the resulting folds produce
geometric patterns.
CHESTERFIELD: An overstuffed sofa with upholstered ends, originally
an English Victorian design.
CHROME TANNED: Leather tanned with chromium salts resulting
in a soft, mellow upholstery leather.
COATED SPLIT: The lower layers which are `split off' of the
top grain layer of a hide can be dyed, finished and embossed to create
coated split leather. This product can be thicker and stiffer than top
grain leather. Since it is also less expensive, it is often used to cover
upholstered sides and backs which do not need to flex and stretch much.
COIL SPRINGS: Wire coils used in quality upholstery to give
a desired resiliency and firmness to the seat and back. These are often
"tied" or incorporated in a "marshall unit".
CORNER BLOCK: Triangular blocks which strengthen important
frame joints.
CORRECTED GRAIN: Top grain leather that has been buffed and
sanded to minimize surface marks, then covered with pigment finish layers
and embossed.
CROCKING: The physical transfer by rubbing of unfixed dye or
loose dyed fibers (especially in suede leather).
CUSHIONS: Loose or attached cushions sit on top of the deck.
The majority of cushions are made up of polyurethane foam. A "marshall
unit," made up of coil springs which are sewn in pockets and then attached,
down or synthetic down-like materials may be used instead of foam in some
upholstery applications. Cushions are normally wrapped or capped (crowned)
with a polyester, low density foam or other soft material for added surface
plushness.
DECK: In conventional (coil spring) constructions, layers of
padding are added on top of the springs or webbing to complete the "deck"
(the area under the seat cushions). In quality upholstery applications,
the deck should be well padded, with no bumps or lumps. The padding should
extend to the front edge of the deck, completely covering the spring edge
or frame.
DIAMOND TUFTING: An arrangement of tufting buttons which yields
a diamond shaped pattern on the back of an upholstered piece.
DOUBLE DOWELING: A construction method where two round wooden
pegs are fitted into holes in two adjacent frame sections.
DRUM DYED: A dying process accomplished by tumbling leather
in a rotating drum to encourage the dye to penetrate fully.
DYED TO SHADE (MILL DYED): A finishing system which produces
essentially the same color on the suede side as the side on which the pigmented
finish is applied.
EMBOSS: To mechanically imprint unique grain effects under
heat or high pressure in order to smooth the grain or give a unique patterned
effect (ostrich, alligator, lizard, etc.). Top grain leather that has surface
imperfections is often buffed smooth and then embossed to restore natural
looking grain pat- terns. These are normally less expensive than full grain
leathers that retain their natural markings.
FALSE ANILINE FINISH: Leather which is fully coated with layers
of pigment finish that provide antique or tonal effects meant to simulate
true aniline finished leathers.
FINISHING: To make leather more durable, clear or pigmented
substances are applied to the dyed hide. These provide abrasion and stain
resistance as well as color enhancement. The finishing process usually
involves three or four coating operations. Generally, the more finish a
leather has, the stiffer (boardier) it becomes. Semi-aniline leathers tend
to be softer than heavily finished leathers, although this can largely
be overcome by milling. Other factors affecting softness include the tanning
formula and hide quality.
FRAME: The skeleton of an upholstered piece. The frame gives
structural support and determines the basic shape of any piece of upholstered
furniture. If a frame is unstable, an upholstered piece will not be durable,
no matter how fine or costly its design, padding, cushioning or leather
cover. Quality frames are generally made of solid wood, but plywood, engineered
wood products, a variety of polymers and metal are also used.
Hardwood frames are usually constructed from kiln dried mixed hardwoods.
White ash is a superior frame making wood. White oak, red oak and American
elm are good, and hard maple and birch are acceptable. Softwoods make poor
frames. Engineered wood products may look like `chipcore' but can be stronger
than hardwood. They are sometimes used at critical stress areas where maximum
strength is needed.
Wooden frame joints are often double doweled, which means that round
wooden pegs are fitted into holes in two adjacent frame sections and glued.
Epoxy coated staples and gang nails are also commonly used. The gang nail
is a metal plate with "saw teeth" which immobilizes the joint when it is
pressed into the wood with a hydraulic press. Major joints need the additional
support of corner blocks which should be glued and screwed into place.
FULL GRAIN: A top grain leather which because it has not been
grain corrected, has natural markings and characteristics. Animal hides
are normally split into a top layer (which had hair on it) and one or more
leather layers that are `split off' from the 'top grain'.
The top grain layer can either be processed into 'full grain' leather
which is not buffed and sanded; or into `corrected grain' leather that
has had the surface markings altered by buffing and sanding.
GLATT: Smooth finish.
GLAZED FINISH; A Finished leather surface is polished to a
high luster by glass or steel rollers under tremendous pressure.
GLOVE LEATHER: Sheepskins tamed to be soft, pliable and supple.
GLOVE SIDE LEATHER: This is side leather that has a garment
finish which approaches that of actual glove leather, but generally has
the same durability as upholstery leather. It is soft, pliable and light-weight.
GRAIN: Markings or patterns on the leather surface. Naturally occurring
grain is caused by wrinkles, markings and pores in the hide. Grain can
also be simulated through embossing and finishing processes.
HAND: The softness or `feel' of a leather.
HAND TIED: Single coil springs that are attached to the welting
with links and then "hand tied" to each other and the frame with twine
to achieve differing amounts of elasticity in the seat. Two, four, and
eight way hand ties are commonly used. The more ways the spring is tied,
the harder the seat.
HARDWOOD FRAMES: Frames which are made from hardwoods such
as ash, oak or birch. These woods are usually kiln dried and resist splitting.
HIDE: A raw or tamed pelt taken from a large, adult animal.
Cattle, buffalo, sheep goat and pig hides have been used to make upholstery
leather, but cattle hides are by far the most common.
KNIFE EDGED: Loose or attached cushion treatment which uses
a single horizontal welt or seam in the middle of the front edge of a cushion.
LEATHER: A hide that has been tanned to render it resistant
to decay, as well as relatively soft and pliable.
LOOSE PILLOW BACK: A pillow treatment which can be removed
from an upholstered piece.
LOVESEAT: Double chair or small sofa.
MARSHALL UNIT: Coil springs which are inserted in separate
pockets and then joined together to form cushions.
MATTE: Dull finish.
MILLING: A natural softening process in which leather is tumbled
in a drum.
MINERAL TANNED: Leathers which have been tanned with any of
several mineral substances, notably the salts chromium, aluminum and zirconium.
MODULAR SEATING: Upholstered seating units which are easily
joined to or arranged with other parts or units to form differant seating
arrangements.
MOTTLED FINISH: The result of blending closely related colors
to achieve a spotty or splotchy appearance.
NATURAL MARKINGS: The subtle markings on leather are analogous
to fingerprints. They distinguish genuine leather from man-made materials.
Other marks which can appear on the surface of leather are healed scratches,
barbed wire marks, wrinkles, brands and insect holes. Gross imperfections
are normally cut out of the finished product. Lower price leathers tend
to have many more markings than premium leather.
NU-BUK LEATHER: A pure aniline leather which has a slight nap,
but is not suede. Nu-Buks are top grain leathers that are more durable
than suede. They are aniline dyed, but since they have no pigmented top
coat, they may be treated with a chemical that promotes water and stain
resistance. Nu-Buk leather should be maintained by occassionally fluffing
the fibers vigorously with a suede brush. A damp cloth can be used to clean
spills, which can then be blotted dry. Soaps should be avoided.
NUDE FINISH: A leather that is usually vat dyed, but has little
or no protective top coat to prevent crocking, cracking or staining.
OTTOMAN: an upholstered seat or couch usually without a back.
PATINA: A luster that naturally occurs when uncoated leathers
age.
PIGMENT FINISH: The coloring of a hide using a coating containing
opaque pigments. The use of pigment finishes insure uniformity of shade
and resistance to fading as well as enhanced stain and soil resistance.
PLATING: The process which smoothes the fnished surface of
a leather or produces embossed surface effects.
POLY DACRON WRAP: A cushion construction method in which a
soft resilient polyester material is wrapped around a polyurethane core.
PROTECTED ANILINE: Protected aniline leather is less expensive
and more common than pure aniline or semi-aniline leather. Its coloration
is more consistent and because it has been coated with protective pigments,
the leather's natural markings are less noticeable.
PULL-UP: When leather is pulled tight during the upholstering
process it may develop areas that become lighter as they are stretched.
This result is known as a pull-up.
PURE ANILINE: Leather that is aniline dyed but has not been
coated with pigmented finishes. It shows all the natural character and
markings.
SAUVAGE: A two-tone effect which adds depth to the leather.
SECTIONAL: Furnituremad up of modular units capable of use
seperately or in various combinations.
SEMI-ANILINE DYED: Term used to describe dyed leather or clear
pigmented coating (finish). It is the premium product which allows the
natural character of the leather to show through.
SIDE LEATHER: Grain leather which has been cut in half forming
two "sides" in order to better accomodate tannery equipment and maximize
the use of hides with flaws.
SNUFFED: Grain leather which, in addition to hair removal,
has had the outer surface lightly removed by buffing.
SOAKING: One step in the processing of raw hides. Soaking restores
moisture to newly received cured hides. This process involves soaking the
hide in water, wetting agents and disinfectants.
SPLIT: The term 'split' refers to the underneath layer of the
hide which has been split off from the top grain. Splits are usually given
a suede or pigment finish, embossed and used for shoes or garments. Split
hides are generally thicker and stiffer than top grain leather and may
be also used in less exspensive upholstered furniture aplications on back
and side panels.
SPLITTING & SHAVING: After hides are tanned and excess
moisture removed, they are fed through a machine which cuts the hide into
the valuable top grain portion and a split layer. After splitting, the
hide is put through another machine which shaves it to a uniform thickness.
STRUCK THROUGH: The dyeing of leather can be controlled by
the manufacturer to either fully or partially penetrate it. Since full
penetration requires more dye, leather that has been fully penetrated is,
therefore, more costly to produce than leather that has only been superficially
(the flesh and grain surfaces) penetrated. Leather that has been fully
penetrated with dye is known as fully struck through leather. If it has
only been superficially dyed, it is called partially struck through.
SUEDE: Leather finished by buffing with an emery wheel to produce
a napped surface. Suede is made from layers split off from the top grain
portion of the hide.
SUEDED PIGSKIN: Sueded pigskins are available in garment weight
and upholstery weight. The upholstery weight is probably the most durable
suede on the market.
TABLE FINISHING: A full pigment finishing system applied on
top of a neutral or contrasting color back.
TANNING: A chemical process which converts the raw hide into
a stable product. This process is often accomplished in large vats or drums.
TANNING AGENTS: Today's upholstery leathers are tanned with
soluble chromium sulfate. Synthetic tanning and vegetable materials derived
from plants and wood (bark tanning) may also be used in combination.
TEE SEAT CUSIONS: A loose seat cushion whose outside front
edges extend laterally in front of the arm of an upholstered piece.
THICKNESS OR WEIGHT: Measured in millimeters which, when divided
by 0.4 is quoted in ounces.
TIGHT SEAT: Fully upholstered seat or backdesigned not to have
a cushion.
TOP COAT: Synthetic transparent polyurethane resins applied
as a protective coating.
TOP GRAIN: Leather which contains the top portion of the hide..the
part that had hair on it. The top grain portion can be processed into full
grain or corrected grain leather. The top grain portion of the hide is
approximately 3/64" or about the thickness of a penny.
TRIMMING: Trmmming, siding and fleshing are operations performed
on the hide which remove excess tissue.
TUFTING: See "button tufted".
UNHAIRING: After soaking hides, hair is removed. Unhairing
destroys the hair root so it comes free from the hide and loosens the outer
skin which covers the grain.
URETHANE FOAM: Flexible polyurethane foam is used as a cushioning
material in upholstered furniture seats,backs and arms. It is an extremely
versatile product that can be produced to have practically any "feel" -
from very firm to plush.
WEBBING: Interwoven natural (or synthetic) strips that provide
a foundation for many upholstered arms, backs, seats and wings.
WELTING: Cord wrapped in fabric which is used to trim upholstery
seams and places where the fabric meets exposed wood.