JEANS - THE BLUE
PHENOMENON
ran a pedlary at that time. So Levi and
his brother followed their parents´
footsteps and also became pedlars.
When the great gold rush began in
1850, however, he decided to take part
and went over to San Francisco in
California.
He took with him a spade, a
pickhammer and a bale of fabric out
of brown sail cloth which was meant
to put up a tent. This did not happen,
however:
Levi found out that the gold diggers´
hard work in the mines made their
clothes get worn out very quickly and
he produced stout working trousers
out of the sail cloth he had taken with
him which he called „half overalls“.
When he continued producing these
trousers he used cheap cotton fabrics
coming from Genova. At that time
Genova was a flourishing place
where cotton was exported all over
the world. The name of the town of
Genova was modified into „jeans“ in
the American slang.
At the end of the sixties of the 19th
century he replaced the brown sail
cloth by an indigo-dyed, wearresistant cotton fabric coming from
France.
The name of this fabric was „Serge de
Nimes“. Serge is the French
expression for a combined twill and
Nimes is the French town where the
fabric comes from. The fabric´s name
Serge de Nimes was quickly turned
into „Denim“ in American colloquial
language.
By
applying
this
indigo-dyed
combined twill the first jeans out of
Denim was almost born - or better
sewn. The only thing missing were
the famous metal rivets.
The application of metal rivets for
jeans is due to the Polish emigrant
Jacob W. Davis, also called Jacob
Youphes. Although the working
trousers out of Denim were stout they
had a tendency to get worn out where
The History of Jeans
When talking about jeans the name
Levi´s is one of the first to be
mentioned. Levi´s which stands for
Levi Strauss is normally called the
forefather of jeans. When tracing
back the history of these trousers to
its origins it is true that Levi Strauss
played an important role concerning
their development and distribution
but he had also other inventive
business partners.
Now the question is: who has sewn
the first jeans and where does the
history of this „blue phenomenen“
begin?
Ill. 1: Levi Strauss in the year 1860
In 1847, at the age of 17 Levi Strauss
left his Frankonian native country in
Germany and emigrated to New York
together with his family. The
members of the Strauss family were
capable and skilful businessmen and
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the pockets were. Jacob Youphes
mended the trousers with a needle
and thread. One day a customer
inspired him to repair the torn off
pockets with the help of rivets. From
then on Jacob Youphes made a lot of
money out of repairing trousers.
Since he was worried that his
invention might be stolen he wanted
to apply for a patent. For doing so,
however, he needed a financially
strong partner. For that reason he
addressed the manufacturer of the
trousers that he mended, Mr. Levi
Strauss. Levi Strauss agreed and
together they applied for a patent to
strengthen the pockets of the trousers
and Levi Strauss acquired a share of
50%.
This patent was written down in 1873
and can thus be called the true year of
birth.
Under the management of Levi
Strauss the jeans were now produced
in series.
Since the trousers were so stout not
only the gold diggers liked them but
– which is not surprising in America the cowboys appreciated them very
much, too. When the trousers were
applied as working trousers for
cowboys, however they got worn out
at the crotch tip. This was no problem
for Levi Strauss and Co. since they
reinforced the trousers again with
metal rivets at the crossing point of
the four seams at the crotch tip.
The metal rivet at the crotch had to be
removed quickly since the way of
living of the cowboys had not been
taken into consideration.
The cowboys used to prepare their
meals at the campfire and then they
spent the rest of the evening sitting
around the campfire. When the
cowboy approached the fire too much
at night, however he quickly learned
the difference between the physical
conductivity of cotton and metal.
Those wearing these trousers were
then suddenly startled out of their
sleep.
By knowing very well the need for
such a stout garment and thanks to
the good cooperation with Jacob
Youphes as well as his very good
instinct for marketing Levi Strauss is
still an important brand name in
today’s textile industry.
The jump across the ocean
In addition to Coca Cola and Rock´n
Roll the Jeans made its way to Europe
with the help of the American GIs.
The distribution took place by means
of so-called „PX-shops“ where only
American soldiers were allowed to
buy.
At that time there was a great demand
for the „American trousers“ as they
were called, especially by young
people. Thus, a trade with jeans
developed and the supplies came
from remaining stock as well as from
auctions of the American army.
The first autonomous attempts to
produce similar trousers on the
European market are due to Albert
Sefranek who came from Künzelsau.
Sefranek who intended to find new
markets for the company of his
parents-in-law,
Messrs.
Luise
Hermann „factory for working
clothes“ regarded the European
version of the jeans a possibility of
completing his assortment.
The first problem Sefranek met with
was to get dress patterns for jeans. So
he went to the infamous station
quarter in Frankfurt and got
acquainted with an American GI in a
bar. On the very same evening he
initiated the first business transaction
with the American soldier. He
ordered 6 original American jeans in
different sizes which he received the
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other day and he „paid“ 6 bottles of
hard liquor for them.
He returned to Künzelsau with the
trousers in his luggage, cut them open
and thus had the dress patterns for
the first 300 trousers. Since the
original Denim was hard to get,
however, because it was very
expensive and importation licences
could hardly be obtained indanthrendyed twill cloth was applied for these
trousers. Due to its very good
fastnesses it was not possible to
obtain the desired used-look even
after the trousers had been washed
several times. In the middle of the
1950´s Sefranek finally succeeded in
importing the genuine Denim from
America.
Together with the distribution of his
own trousers Sefranek tried to make a
contract with Levi´s which was
supposed to secure him the right to
sell the original jeans in Europe. By
travelling to the USA and by
negotiating with Max Katzburg who
was then the exporting manager of
Levi´s
he intented to lay the
foundation stone. With the consent
given to him by Katzburg he travelled
back home and ordered the first
20.000 trousers. Shortly before they
had given their final consent,
however, Levi´s withdrew their
consent and granted the licence to
Messrs. Paterson Clothing. For that
reason Sefranek concentrated on
distributing his own trousers which
soon appeared under the name of
„Mustang“.
Until the end of the sixties the
importation of finished articles out of
cotton was subject to strict import
restrictions.
When
this
legal
instruction was no longer valid
mainly American companies such as
Lee, Lois or Wrangler placed their
articles on the European market by
opening their own branches.
In the 70´s the boom for jeans began.
Up to this time they had mainly be
considered to be working clothes and
young people had used them to
demonstrate the „American Way of
Life“; now the established readymade clothing factories and fashion
shops also used their chance. Very
expensive marketing campaigns led
people believe in a certain lifestyle
when wearing jeans.
In the year 1977 the first designers ´
jeans were placed on the market and
until the beginning of the 80´s the
basic jeans was modified almost
beyond recognition. When there was
a comeback of the classical, plain
form in the middle of the 80´s the
jeans became popular for Yuppies
who preferred luxurious trademarked articles.
So much for the history of jeans.
From yarn to grey fabric
Production of the yarn
The classical jeans is produced out of
indigo-dyed Denim fabric. The
special character of this fabric – only
the warp thread is dyed – makes it
necessary to carry out dyeing in yarn
form.
The yarns applied for Denim were
exclusively
produced
on
ring
spinning machines in former times.
The development of OE yarns - by
applying smaller rotors with a
spinning speed of up to 200 m/min has led to the application of OE rotor
yarns both for warp and weft.
The yarns applied for weaving must
be of high quality: a high fibre
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strength, regularity as well as a small
part of short-stapled cotton fibres
belong to the basic features of the
Denim yarn.
For regular jeans qualities the warp
yarns are spun in a fineness of 50 to
90 tex, for the weft yarn the
finenesses are mainly 75 to 120 tex. If
Denim is made out of Tencel or
Modal especially for jeans shirts the
finenesses are up to 25 tex.
replaced the woad which was one of
the most important dyeing plants up
to this time.
Only the leaves were used for good
qualities whereas the leaves together
with the stalks were applied for
normal qualities.
In a vat filled with water and partially
with human fermented urine as alkali
donor stems and leaves were exposed
to a putrefactive process. During this
putrefactive process hydrogen was
created by means of micro-organisms
which, as a reduction agent,
transformed the dyestuff contained in
the Indigo plant into a water-soluble
form.
When this process was over the whole
mass was filled into a liquid where
the fermented mass was stirred with
poles. The reason for doing so was to
transform the Indigo into its waterinsoluble form again by air oxidation.
In a last step the water-insoluble
dyestuff particles could then deposit
on the bottom of a stationary vat.
Indigo
Special attention shall be paid here to
Indigo, the „king of dyestuffs“ since
it plays an important role in
obtaining the jeans effect.
Indigo belongs to the category of
water-insoluble dyestuffs.
It was first mentioned in a book 13
BC; at that time the name Indian blue
indicated the country the colour came
from. It is said to have been used for
dyeing in India and China 2000 years
BC already.
The Indigo plant is used for
preparing Indigo (ill. 2).
Then the liquid standing above was
drained and what was left was a thin
mash which was dried in the open air
and was put on the market in pressed
or in powder form (ill. 3).
Ill. 2: Indigo tinctoria L.
Ill. 3: Trading form of Indigo at that time,
approx. 9 cm length of edges and 163 g in
weight
This plant came to Europe in the 16th
century via India and gradually
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When looking at these methods one
can
easily
imagine
that
the
production of Indigo was considered
to be an evil-smelling trade.
O
H
N
N
H
In 1880 Adolf von Baeyer succeeded
in carrying out the first synthetic
production of Indigo. In the year 1897
the
“Badische
Anilinund
Sodafabrik“ in Ludwigshafen - which
is nowadays called BASF - was able to
carry
out
an
industrial-scale
production of the Indigo dyestuff for
the first time. A few years later this
synthetic dyestuff replaced the Indigo
coming from British-India almost
completely.
As was already mentioned Indigo is a
dyestuff insoluble in water. In order
to be able to apply it on cotton it must
be transformed into a water-soluble
form.
Similar
to
the
former
production of Indigo this is done by
reducing the dyestuff (ill. 4). In
practice this is nowadays carried out
with
sodium
dithionite
or
hydroxiacetone in the alkaline range.
O
Indigo
Oxidation
Reduction
HO
H
N
N
H
OH
Water-soluble leuco form of Indigo
Ill. 4: simplified description of the
reduction/oxidation of Indigo
In former times dyeing with Indigo
was carried out in wood or metal vats,
normally in rope form. (ill. 5).
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Ring spinning
X-Cones
Rotor spinning
Ball warper
Rope Creel
Indigo – Continuous dyeing
Warp size impregnation
Weaving
Control
Long chain beamer
Aftertreatment
Sanforizing
Ill.6: Indigo Rope Dyeing
When dyeing according to the rope
dyeing or cable dyeing method (Ill. 6)
350 - 400 warp threads are bound on
the ball warper to very thick cables of
10 000 - 15 000 m length. On the
continuous dyeing installation, 12 to
36 cables are led side by side, wetted,
dyed and dried after the dyeing
process on cylinders and put into
cans. Then the cables are dissolved to
warps on the long chain beamer. The
warps
are added to the sizing
machine, sized and then led together
to warp depending on the total
numbers of threads.
In practice, this method has proven to
be very good through obtaining an
optimum indigo dyeing. However it
is important that the cables have a
constant tension in order to avoid
warp stripes. The disadvantage
compared to other methods is that
yarn breakages do occur more often.
Size of the dyeing unit is between
60 - 80 m. Normally, 6 dyeing vats are
in use. There are nevertherless
variations with 3 to 8 dyeing vats.
Ill. 5: Indigo sample dyer
As very clearly visible on the above
picture, at the bottom side of the rope
the water-soluble Leukoform of the
indigo is yellowish and on the side of
the rope oxidized with air the indigo
blue can be seen again.
Nowadays, yarn dyeing with indigo
is done continuously. Here the
various dyeing processes with
different concentrations of chemicals
as well as the subsequent yarn sizing
exert an influence on the quality and
the appearance of the ready fabric.
There are three processes in the
practice for continuous dyeing:
• Rope Dyeing
• Slasher or Sheet Dyeing
• Loop Dyeing
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parallel next to each other. These are
much smaller compared to the rope
dyeing machines. Another advantage
is that the cables don’t need to be
open after dyeing.
Moreover, each yarn wets much faster
and in this way reduces the dipping
and wetting times during dyeing.
All in all, each thread has a larger
surface compared to a dyeing cable
and this requires somewhat more
hydrosulphite to prevent a premature
oxidation of the indigo.
Rotor spinning
Ring spinning
Weaving
X-Cones
Control
Ball warper
Singeing
Sanforizing
Ill. 7: Indigo Sheet or Double Sheet
Dyeing (Slasher Dyeing)
When dyeing according to the sheet
dyeing method, instead of cables the
warp threads are fed to the machine
Air passage
Beam carrier
Wetting
Indigo-dyeing
Ill.8: Loop Dyeing 1 for 6
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Rinsing baths and sizing
Whereas during rope and sheet
dyeing the garns are always led in
succession to the dyeing baths, the
fabric of the loop dye method (Ill. 8)
is led several times through the same
dyeing bath. The machine is then
much shorter and the hydrosulphite
consumption is lower. Depending on
the number of dyed passages and the
concentration of indigo in the dyeing
vats, different dyeings of the yarn
result (Ill. 9).
3 g/l Indigo
Ill. 10: Fibre cross-section of a yarn dyed
with Indigo
1 passage
The sizing process follows the dyeing
process of the yarn, this is already
visible by the machine sequences and
is necessary to stabilize the warp
thread against the high mechanical
stress while the weft thread is being
fed. For sizing the warp, PVA, CMC
and acrylate sizes are used besides
starch-containing products.
2 passages
4 passages
6 passages
6 g/l Indigo
4 passages
After sizing, the dyed warp is woven
with the non-dyed weft yarn.
About 2/3 of all weaving machines in
the world for denim are Sulzer Rüti
Projectile weaving machines (Ill. 11).
6 passages
Ill. 9: Indigo dyeing with various
passages and dyestuff concentrations
The dyeing methods described here
do not allow a total penetration of the
dyestuff during the short dyeing time
and give the desired and necessary
ring dyeing important for the jeans
effect (Ill. 10)
Ill. 11: Sulzer Rüti Projectile weaving
machine
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To achieve a finished width between
150 and 156 cm, weaving machines
with a reed width of 160 to 167 cm are
used. The speed of the weaving
projectile
can
go
up
to
1 430 m/min and this complies with a
speed of 86 km/h.
6 - 8 oz
9 - 11 oz
The classical denim consists of a 3/1
side twill (Ill. 12). In succession three
and one weft threads are put under a
weft thread. Staggered by one warp,
the typical twill with one degree from
below left to above right, also called
„Right-Hand-Denim“ results.
Ill. 13: Summary of various denim
qualities
12 - 14 oz
14, 5 - 16 oz
very light denim for shirts
light denim for trousers of
summer quality
medium denim for trousers,
standard quality
heavy quality, socalled bull
denim, mostly for jackets
Trousers and other clothing are
manufactured
with
the
denim
material. With help of a pattern
computer all parts for one trouser are
made and then either printed by
plotter on paper, cut and then the
pattern is put on the fabric or fed
directly to the cutting machine. Up to
30 pieces are required for a normal
five pocket jeans.
To cut each piece, 50 to 70 layers of
fabric are placed on top of each other
by a laying-up machine. This
machine then saws all pieces in
accordance with the pattern. Then the
trousers are sewn together by the
seamtresses. Each seamtress is
specialized in a certain part of the
trousers, e.g. pockets, front part, belt
loops etc. The entire sewing process
for one pair of trousers takes about 10
minutes.
Ill. 12: 3/1 Twill weave
Different kinds of finishing processes
can follow after weaving depending
on what the clothier wants.
The denim is usually brushed directly
after weaving to remove the fibre
fluff from the weaving process. The
fabric is also stretched and sanforized
to minimize the crosswise and width
shrinkage.
Further Processing
The first jeans trousers went directly
from the sewing room to the shops
and were stiff as wood. This
remained so up to the beginning of
the seventies.
The first thing after buying a pair of
jeans was to jump into the bath tub
with the new jeans. The „shrink to
fit“-treatment made them fit exactly
to body form.
Depending on the yarn thickness and
weaving density, denim is divided up
into various weight classes. This
weight class is expressed in onces,
whereas one English once (oz) is 28.35
g. The weight chosen depends on the
manufactured article (Ill. 13).
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The right look needed several
household washings. Washed out
jeans were „good looking“ and
individual because almost every pair
had its own look.
Not to forget the first bleaching trials
with toilet cleaning agents that left
back non-removeable traces in the
bath tub.
The so-called „used-look“ was asked
for and washing companies that gave
raw trousers an artificial ageing
process were jumped out of the
grounds by the dozen.
In these factories the trousers were
given a full-step treatment like
desizing, several washings and
bleaching.
Ill. 15: Lapauw in deloading position
The pumice stone
This is done today in over
dimensional big washing machines,
so-called drum washing machines (Ill.
14). The capacity of such drum
washing machines can be up to
200 kg fabric which complies with
about 250 trousers depending on the
sizes. Most common are however
batch sizes of approx. 150 trousers.
Towards the end of the 70ies, pumice
stones were discovered to accelerate
the ageing process of indigo-dyed
parts. No one exactly knows if the
Japanese or the English first created
the „stone-washed look“.
The pumice stone is a magmatic
extrusive rock. It originates from the
very gasy beginning phase of a
volcanic eruption. when the outer
crust is thrown out in the atmosphere
quite far. Its origin is up to 15 000
years back depending on the region.
Most of them originate from Greece,
Turkey, Iceland and small quantities
can be found on Tenerife, the Azores,
Philippines, Indonesia, China and
Japan, Ecquador, Mexico and USA.
Looking at where these pumice stones
come from, you can imagine how
different each character is.
Abb 14: Lapauw drum washing machine
Pumice stones have the following
chemical composition:
Some of these washing machines can
be tilted to the front with running
drum for emptying (Ill. 15).
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partially separated: the undyed inside
of the fibre comes to the surface.
Moreover, the surface gets a softer
handle through the mechanical
process with pumice stones.
55 - 75 % Silicium oxide
10 - 16 % Aluminum oxide
3 - 6% Sodium oxide
Portions of potassium oxide, calcium
oxide und iron oxide
How many stones are used for the
ageing process of the trousers
depends on the desired effect.
Usually, the normal to double
quantity of pumice stones is used
with regard to the fabric weight.
Treatment with pumice stones also
brought some disadvantages.
The sheets built in the drum washing
machines had a high abrasion.
During the beginning phase it did
happen quite often that a batch of
jeans was taken out of the machine
that was totally torn from the ripped
sheets.
Large amounts of sludge together
with fibre residues and indigo
pigments
accumulated
during
treatment with pumice stones that
had to be disposed.
Deloading the machine after stone
treatment was very difficult because
stones and their split off remainders
were all over and had to be removed
from the trousers. This was mostly
done by hand, sometimes de-stoning
units are applied.
Last but not least, pumice stones are a
natural raw material and their
occurrence is limited.
Through the gases originating during
stone formation, a foam-like and
porous structure was formed.
These pores again have very sharp
edges which give the stone its
abrasive property (Ill. 16).
Ill. 16: Turkish pumice stone, original
diameter approx. 5 cm
The pumice stones give the jeans
trousers during the washing process
the desired appearance in much
shorter time as if it were washed
many times.
Depending on the application field,
pumice stones with a 2 to 3 cm
diameter are used for finer denim
qualities, e.g. shirts. The common size
for normal denim qualities is
between 3 and 6 cm diameter.
At the end of the 80‘s the progress in
biotechnology made it possible to
apply
enzymes
for
enzymatic
stonewash.
The trousers must first be indigodyed to get a stone-washed look. The
indigo dyeing of the yarn only takes
place in the outer area, as already
described. During treatment in a
machine with pumice stones, the
outer most layer of the yarn is
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