How To Dye Cloth
Ever since clothes were developed people have found ways to enhance their
own appearances and express beauty by adorning or decorating their garments.
Painting, dyeing, stitching, and attaching ornaments are just some of the
ways people have decorated clothes. Today many individuals still think of
clothes as more than just body coverings. The clothes people wear show that
they are concerned with appearance and the expression of beauty.
The techniques, or methods, for decorating clothes developed many centuries
ago, were hand methods. Some are still done by hand today, although many
have been modified, or changed, to be done by machine. Other techniques
once used to decorate clothes are no longer in use today. However, many
museums have collections showing examples of these and other ways people
have decorated clothes.
Painting with dyes made from natural materials made in the environment has
been done for thousands of years. The Polynesians painted designs on tapa
cloth, or bark cloth, made from the paper mulberry tree. Indians who lived
in the plains regions in North America painted animal skins that they prepared
for clothing. Today people still do hand painting on fabric, but machine
methods of painting designs and colours are used for producing large quantities
of fabrics.
History of Dyes
Until the mid-19th century, all dyes were derived from the leaves, twigs,
roots, berries, or flowers of various plants or from animal substances.
Tyrian purple, used by the Phoenicians in the 15th century BC, was produced
from certain varieties of crushed sea snails. The use of indigo as long
ago as 3,000 BC has been documented; synthetic indigocis still an important
dye because it is exceptionally fast.
The textile dyeing industry in Europe originated in the 16th century. when
the Portuguese, Dutch, and English introduced indigo. Natural dyes such
as Cochineal, Turmeic, Wood, Madder, and Henna remained the primary source
of dye colours until the discovery of the first synthetic dye in 1856 by
Sir William Henry Perkin.
Perkin, an English chemist, was working with the coal-tar derivative ANILINE
when he accidentally discovered that a by product of aniline oxidation had
dyeing capabilities. He established a factory to manufacture his new purple
dye, mauve; other experiments began to produce new colours from aniline and
other coal-tar derivatives. Alizarin was the first natural dye to be produced
synthetically, (1868), and by 1880 indigo had been synthesized. By 1916,
an extensive technology had developed, most of it concentrated within a
German cartel that held a virtual monopoly over dye production. Only with
the onset of World War II did Germany lose its position as the world’s
principal supplier of dyes. Today, the U.S. dye industry, aided by the post-World
War II acquisition of German technology, has become a major exporter of
dyes.
By 1881 Perkin had synthesized glycocoll, cinnamic, courmarin, and several
unsaturated acids. In 1878. this latter work resulted in the “Perkin
synthesis,” the preparation of unsaturated acids by the condensation
of an aromatic aldehyde with the salt of a fatty acid. The synthesis of
coumarin was of special importance, being the first vegetable perfume ever
produced from coal-tar, Perkin also undertook a comprehensive study of optical
isomerism. From 1881 to the end of his life he devoted himself to a study
of magnetic rotation, a tool to prove invaluable in determining organic
structures.
Mordants are chemical substances formerly used to confer affinity for textile
fibres to natural and early synthetic dyes. Alizarin, applied with an aluminum-salt
mordant, was used extensively to produce bright red shades on cotton. Tannin
and sodium stannate were used to form insoluble salts with basic dyes on
silk. Chromium still is used to a limited extent in the United States, and
to a greater extent abroad, with azo and basic dyes for the dyeing of wool
and the printing of cotton. Chemically the quantity of a substance having
the weight in grams numerically equal to its modular weight refers to mole.
A mole of a substance contains 6.02257 x 1023 molecules. Given
this formula, the types of dyes can be clearly discussed in the following
section.
Types of Dyes
Dyes may be classified according to their manner of application, the fibres
for which they are used, or their chemical structure. Almost all dyes, however,
fall into one of the following categories:
Vat dyes are extremely fast dyes applied particularly to
cotton. The water-insoluble dye is reduced in a vat to a water-soluble compound.
After the fabric is dyed, it is exposed to air or to a chemical oxidizing
agent, and the dye reverts to its insoluble form.
Sulfur dyes, used to produce deep shades on cotton, are
inexpensive dyes made by the reaction of various organic chemicals with
sulfur or sodium sulfide.
Direct dyes are azoic dyes to which common salt or sodium
sulfate has been added; they can be applied directly to cotton or other
cellulosic fibres such as flax, jute, or paper, without pretreatment of
the fibre with a mordant.
Acid dyes are used for wool, silk, and some synthetics.
Unlike the vat and sulfur dyes, they are water-soluble and can be applied
directly to the fibre.
Disperse dyes soluble in acetate but not water, are used
to dye polyester, polyamides, and other synthetic fibres.
Basic dyes include most of the first synthetic dyes. They
are cationic (that is, they have a positive electrical charge) and are used
for anionic (negative-charge-bearing) fabrics such as wool, silk, nylon,
and acrylics. They are particularly brilliant, and most fluorescent dyes
are basics.
Metal-complex dyes, used primarily on wool, are combinations
of a dyestuff and a metal, usually chrome. In use since the 1940’s,
they were developed from the older mordant dyes and are highly light-and
wash-fast.
Reactive dyes, the newest dye class, function in an entirely
different manner from other dyes. Ordinary dyes adhere to their substrate;
reactive dyes become a part of the substrate molecule (and they are, therefore,
exceptionally fast). The most important in this group are the azo dyes,
a group of organic compounds whose dyeing properties are based on their
linkage by a nitrogen, or azo bond. Thousands of azo types have been developed
for use on every type of fibre. Azoic dyes are azo types developed specifically
for cellulose fibres.
Azo Dyes. The next major breakthrough came with the utilization
of the diazo reaction in the formation of synthetic dyes. The diazo reaction
had been discovered by the German chemist Peter Griers in 1858, when he
Observed that aromatic amenities (R.NH2) could be readily converted to diazonlum
compounds (R.N=N.C1) under appropriate conditions.
Some azo dyes are used with mordants. In this case, chelating metals are
used with the dyes to achieve both light-and wet-fasthess. Without the chelating
group the azo group is open to photochemical attack and the chromogen can
be destroyed. This possibility can be reduced considerably by incorporating
a chelating system, usually the O-O’ dinydrcxy azo system, into the
molecule to chelate a metal atom.
Natural Dyes
Although the natural dyes are of a chemical and historical interest, in
most dyeing operations they have been almost completely replaced by synthetic
colours, which are generally purer, less expensive, and more colour fast.
However, logwood, and turmeric, are still used to a limited extent. Of the
three classes of natural dyes, plant dyes are by far the most numerous and
mineral dyes the least numerous. The plant dyes are Obtained from the members
of many different botanical families and from different parts of these plants.
Two of the most important plant dyes, indigo and madder (now called alizarin),
are now produced from coal-tar and are valuable articles of commerce. The
early use of indigo in widely dispersed areas have been proved by the unearthing
of indigo-dyed fabrics from Egyptian’s tombs and from the graves of
the Incas of Peru. This blue dyestuff was Obtained from the leaves of plants
of the genus Indigofera, a species of which was cultivated in India thousands
of years ago. Indigo was introduced in Europe in 1516. At first it competed
with, but eventually it supplanted, another blue plant dye that was obtained
from wood, which was probably the earliest plant to be grown solely for
its pigment content.
Alizarin is the active ingredient of the famous Turkey red dye, which for
centuries was the fastest and most brilliant red dye known. Alizarin was
Obtained from the madder plant, Rubia tinctorum, which was formerly cultivated
extensively in France, Belgium, and Turkey. After the synthesis of alizarin
in 1868, the production of the natural dye decreased rapidly, eventually
ceasing altogether.
Probably the most famous, and surely the most expensive dye of ancient times
was Tyrian purple, an animal dye. It was Obtained from a small sac in the
body of a snail-like marine mollusk, Murex brandaris, found along the shores
of the eastern Mediterranean. Each mollusk shell had to be broken individually,
and each small sac of 3,880,000 mollusks were require to make a single pound
of the dyestuff. Only royalty and the very wealthy, therefore, could afford
to wear apparel coloured with this dye, hence the expression “born
to the purple.”
Application Of Dyes
Preparation of Fibers. Most fibres require
some preliminary treatment before they are dyed. Wool, for example, requires
thorough scouring with soap and soap ash to remove dirt and grease. Sometimes
the vegetable impurities in wool are removed by immersing the fibre in dilute
sulfuric acid, drying it, and then heating it to 110°C. (230°F.). This is
called carbonizing. Sometimes the wool is bleached or stoved (exposed to
sulfur dioxide gas) prior to dyeing.
Raw cotton contains natural
waxes and other noncellulosic impurities. These are generally removed by
a process called kier boiling, which consists of boiling the cotton in a
special autoclave, or kier, under pressure with a dilute solution of caustic
soda, soap, or other alkali. Cotton threads are usually starched, or sized,
to facilitate weaving; the starch must be removed before dyeing, and this
is usually done by fermenting the starch in enzymes. Other processes that
are often used on cotton before dyeing are bleaching with sodium hypochlorite
and dilute acid and singeing to remove fine fuzzy projecting fibres.
Viscose rayon yarn,
in the form of skeins, cakes, or loose yarn, seldom needs predyeing treatment.
Woven or knit goods, however, are treated with a hot ammonical soap solution
to remove the gelatin size. Acetate rayon is often scoured with soap and
ammonia, and nylon rarely needs prelillnary treatment prior to dyeing.
Raw natural silk contains a gumy
substance called sericin. Before the silk is dyed, the sericin is removed
by a process called boiling off, or degumming, during which the fibre is
heated in a dilute soap solution for two hours or more. Silk is sometimes
weighted with tin salts to improve its luster and draping qualities.>
Dye Operations And Machines
Although dyeing was formerly a hand operation, and still is
in homes and labouratories, commercial operations are now performed almost
entirely with machinery.
Dyeing machines are of two main types, those in which the material to be
dyed is moved through the dye solution and those in which the dye solution
is circulated through the material. However, in some of the newer machines,
there is movement of both the material and the dye solution.
There are three basic methods for moving the material
through the dye solution.
In one of these, hanks of the material to be dyed are fastened to a wheel,
which rotates them through the solution. In another method, the material
is drawn up and down over a series of rollers immersed in the solution.
In a third method, cloth that is wound around one roller is passed into
the solution, under a guide roller beneath the surface of the liquid, and
then rewound on another roller. There are variations of each of these methods.
There are also several methods for circulating
the dye solution through the material.
In one of these, loose fibres are placed in perforated containers through
which the solution can be circulated. In another method, hanks of yarn are
fastened to a frame, which is then lowered into a tank through which the
solution is circulated by propellers.
Union Dyeing.
Unions are materials woven from two or more different kinds of fibres, such
as cotton and wool or viscose and acetate rayon. One means of dyeing unions
is to dye each kind of fibre separately with the appropriate kind of dye
and then to weave the coloured yarns into cloth.
Excellent results are obtained by this method, but it is relatively expensive.
Another process is to weave a dyed fibre with an undyed one and then complete
the colouring operation by dyeing the cloth. The commonest and most economical
method, however, is to dye the union in a bath containing the right mixture
of dyes that will colour all components of the mixed fabric to the desired
shade.
Because of the large number of fibres available, it is evident that choosing
the correct dyes and dyeing conditions for colouring the many different kinds
of unions now on the market requires the greatest technical skill on the
part of the dyer.
Textile Printing
Textile printing is of the greatest commercial importance. Essentially,
it is the application of dyes to cloth in definite patterns.
s has been practiced in India and China for countless
centuries and is still in use to a limited extent. This process is similar
in principle to ordinary letterpress printing, in which the raised portions
of prepared blocks receive dye and then transfer it to the material to be
printed. Attractive prints may be obtained by skilled workers, but the process
is slow and not easily adapted to quantity production.
Stenciling
Stenciling is another method of applying coloured patterns to cloth. A popular
variant of this process. silkscreen printing, has long been practiced in
Japan and is now much used in the United States by artists, and to some
extent by commercial firms, to achieve special effects. In this process
the design is first traced on a silk screen, and the portions that will
appear uncoloured are lacquered. Dye paste is then rubbed over the surface
of the screen and penetrates the unlacquered silk to give the desired pattern
to the cloth beneath the screen. A separate screen is needed for each colour.
Attaching the Stencil
Before you start to stencil you must first ensure that all the edges of
the design can be kept in close contact with the surface which you wish
to stencil. This is to stop your paint from seeping under the edges and
spoiling the clean outline of your design. The fine spray of spray paint,
for example, will drift under the smallest part of a loosely attached edge,
so great care must be taken at this stage. A beautifully designed stencil
can easily be blurred and spoilt by hurrying.
One of the most effective ways of attaching stencils is to use an aerosol
adhesive, generally available in larger graphics and art supply shops, which
coats the surface with a thin layer of light adhesive that remains tacky
for some time. The stencil can therefore be stuck down and lifted off a
surface a number of times without damage to that surface.<
Place the stencil, reverse side up, on a sheet of newspaper and spray the
glue thinly and evenly all over it. This process is easier if done against
a vertical surface such as a door, since this prevents the nozzle clogging.
Let it set for a few moments. When you are ready, position the stencil accurately,
glued side down, on the surface you are to decorate.
Some people may prefer to attach the stencil with dress-making pins. They
take more time, but are far cheaper and, perhaps, more readily at hand.
Tap them in with a small hammer at intervals along the cut edge of the design.
They should only be inserted to the point at which they will stand firmly
without support and can be pulled out easily with your fingers.
Batik is a dyeing process developed many centuries
ago in the Indonesian island of Java. Batik dyeing is done by covering parts
of cloth with wax before the cloth is dyed. The waxed areas do not absorb
dye and leave a pattern of uncoloured areas against a dyed background.
Batik is still done in some areas of the world and by people who enjoy producing
handcrafted products. The appearance of batik can be illtated by factory
processes which produce thousands of yards of fabric rapidly. The batik-like
fabric sold in fabric stores and used for ready to-wear garments has probably
been produced by printing the design on the surface of the fabric in a factory
process. Hand produced batik may be found in some specialty shops and import
stores.
Ikat, or tie-dyeing, is another
process using dye for decorating cloth. This art was developed in Japan
and India more than a thousand years ago. To tie-dye, parts of cloth are
folded and knotted or tied in such a way that the tied areas do not absorb
dye when the cloth is put into the dye solution. When the tied areas are
loosened they leave an uncoloured pattern on the dyed background.
Many fabrics today which appear to be tie-dyed are made by machine. However,
like the batik process, tie-dyeing by hand is still done today. The Yorubas
of Nigeria are skilled in ornamenting cloth with individualized patterns
using the tie-dyeing process. You may have tried tie-dyeing or may know
someone who decorates fabric in this way.
Tyanting dyeing
The cloth is elabourately washed and soaked to secure the right texture and
surface and is then hung over a frame, the artist, usually a woman, sitting
cross-legged before it. The design is sometimes first sketched in charcoal,
but the heat artists use only their tyantings, relying on visual memory.
They outline the area that is to be dyed and cover the rest of the surface
with wax. The cloth is then immersed in cold water till the wax hardens
and is afterward dipped in the dye vat. The wax is removed, leaving exposed
other parts of the cloth to be dyed different colours by the same process.
The traditional colours are indigo blue, madder red and brown; secondary
colours are produced by dyeing one colour over another.<
Block Printing
The origin of block printing on textiles is somewhat Obscure but it is clear
that the printing of textiles by means of blocks was developed from free-hand
painting with a brush. Wooden blocks believed to have been used for textile
printing have been found in burying grounds at Akhmim, upper Egypt, and
are said to date from the 4th century A.D. No textiles printed by means
of these blocks have, however, been found. In Europe, block printing of
fabrics does not appear to have begun much before the end of the l2th century
A.D.; the chief center appears to have been the Rhineland of Germany.
In blocks used for printing, the spaces between the lines or devices forming
the pattern were cut away, leaving the design standing in relief, as in
letter-press printing. The colour was then applied to the surface of the
block and the coloured block pressed down on the cloth. The pigments were
mixed with starch, gum (tragacanth) or a mixture of these, or even with
varnish, so that the colour was in a viscous state and did not run from the
raised portions of the block. Cennini describes how the outlines of the
patterns were printed by block and additional colours added by means of a
brush.
One of the clearest expositions of block printing in the “madder style”
is given in the supplement to John Barrow’s New and Universal Dictionary
of Arts and Science. The cotton or linen was printed with chemical substances
known as mondants, which on immersion in the vat reacted with the soluble
dye to precipitate an insoluble colouring on the cloth fibres so that the
colour remained permanently fixed in the mondant-printed areas while the
dye taken up by the unmordanted parts could be easily removed by washing.
In madder dyeing, different mordants can produce various shades of reds,
pinks, purples and browns from a single immersion in the dye. The different
mondants were printed one by one, the printer moved along the whole length
of the cloth printing the first mordant from one wood block, then the second
mordant from another block, and so on, until the whole pattern was completed.
The mordant-printed cloth was then immersed in the dye.
The reds, browns and purples were produced by printing varying strengths
of alum and eron mordants, followed by immersion in the madder dye. Yellows
and drabs (light, brownish colours) were produced by the printing of similar
mondants followed by dyeing with weld, also known as dyer’s weed.
Blue was produced by “penciling-in” indigo with a brush. This
operation was usually carried out by women or girls.
All greens were produced by the penciling-in of indigo over yellow. To save
expense, the yellows were often blocked or painted in to avoid an additional
dyeing but with this method the yellow dye was fugitive and in many extant
l8th century textiles the yellow has almost entirely disappeared.<
| Name | Color | Source | Used On | Class |
| Annotto | Orange-red | Seeds of Plant | Cotton | Direct |
| Berberill | Yellow | Seeds of the Barberry shrub | Cotton, Leather and Silk | Mordant |
| Brazilwood | Brick-red | From the tree |
Cotton and Wool | Direct |
| Chrome Yellow | Yellow | From the mineral crocoite | Cotton | Direct |
| Rustic | Yellow-gold | Mulberry tree | Cotton and Wool | Mondant |
| Iron buff | Buff | Mineral containing iron sulfate | Cotton | Direct |
| Kermes | Scarlet | Insect | Cotton and Linen | Direct |
| Lac | Red | Insect | Cotton and Linen | Direct |
| Log wood | Purple Blue to Black Violet to Black |
Heartwood of the tree | Wool, Cotton and Silk | Mondant |
| Turmeric | Yellow | Tubus of the herb | Cotton, Linen Silk, and Wool | Mordant |
Classes of Dyes Used on Major Textile Fibers
| Acetate | Acid | Azoic | Basic | Developed | Direct | Sulfur | Vat | Mordant | |
| Acetate | P | S | S | ||||||
| Acrilon | P | S | |||||||
| Cotton | P | P | P | P | P | P | |||
| Dacron | P | S | S | ||||||
| Dynel | P | S | S | S | |||||
| Linen | S | P | P | P | P | ||||
| Nylon | P | P | S | S | S | ||||
| Orlon | P | S | S | S | S | S | |||
| Rayon | S | P | P | P | P | P | P | ||
| Saran | P | ||||||||
| Silk | P | S | S | P | P | S | P | ||
| Wool | P | S | S | P |
P: preferred use; S: secondary use
Chemical Classification of Synthetic Dyes
| Class | Chromophore | Approximate Number of Shades |
Principal Use |
| Acridine | >C=N-and>C=C | 1,000 | Textiles and Leather |
| Aminoketone | O=C-HN2 | 1,000 | Intermediate |
| Anthraquinone | >C=O and>C=C | 15,000 | Textiles |
| Azine | -C-N=C- | ||
| -C-N-C- | 1,000 | Textiles and Leather | |
| Monazo | One -N=N | 9,000 | |
| Disazo | Two -N=N- | 9,000 | |
| Azo Trisazo | Three -N=N | 5,000 | Textiles |
| Polyazo | Four or More | 2,000 | |
| -N=N- | |||
| Azoic | -N=N | 3,000 | Textiles |
| Diphenylmethane | >C=N | 1,000 | Textiles |
| Hydroxyketone | 0=C -OH | 1,000 | Intermediate |
| Indamine | two)C=N | 300 | Intermediate |
| Indigoid | O=C-C=C-C=O | 1,000 | Textiles |
| Indophenol | >C=N-and>C=O | 300 | Color Photography |
| Lactone | >C=O | 1,000 | Wool |
| Methine | >C=C | 1,000 | Paper and Photography |
| Nitro | -NO2 | 700 | Textiles |
| Nitroso | -N=O =N-OH | 300 | Textiles |
| Oxazine | -C-N=C | 1,000 | Calico printing |
| =C-O-C= | |||
| Phthalocyanine | >C=N | 1,000 | Paper |
| Quinoline | >C=Oand>C=N | 1,000 | Paper and Wool |
| Stilbene | -N=N-and>C=C | 1,000 | Cotton |
| Sulfur | =C-S-0= | 2,000 | Textile |
| =C-S-S-0= | |||
| Thiazole | >C=N-and-S-0= | 400 | Intermediate |
| Triarylomethane | >C=AR=NH | 3,000 | Cotton, Silk, Wool |
| >C=AR=O | |||
| Xanthene | -O-C6H4-0 | 1, 000 | Cotton, Silk, Wool |
Appendix D
Glossary:
Acid—any compound that reacts with a base to form a
salt, produces hydrogen ions, turns blue litmus paper red
—used in medicine and in making dyes
Anthracene—a product of coal-tar distillation used
in making dyes and as a radiation detector
Azoic—contains the nitrogen radical -N:N(azo dyes)
Bast—fibre obtained from phloem
Bice—a grayish blue, duller than azure
Carotene—any of three red or orange-coloured hydrocarbons
Chrome—any of certain salts of chromium, used in dyeing
and tanning
Cloth—a woven, knitted, or pressed fabric of fibrous
material, as cotton, wool, silk, hair, synthetic fibres, etc.
Colorant—anything used to give colour to something else;
pigment, dye, etc.
Cyan—blue (containing cyanogen)
Elastomer—a rubberlike synthetic polymer, as silicone
rubber
Hemp—a tall Asiatic plant having tough fibre in its
stem
Kermes—the dried bodies of certain Mediterranean insects,
used to make a purple-red dye; the dye
Solubilized—the condition or extent of being soluble;
the amount that can be solubilize
Tint—a delicate colour or hue; tinge; a colour or shading
of a colour
Twig—a small branch or shoot of a tree or shrub
Tyrian—a purple or crimson dye used by the ancient
Romans and Greeks; bluish red
