Dye

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Dye

A dye can generally be described as a color

Color

Color or colour is the visual perception property corresponding in humans to the categories called red, yellow, blue and others....
ed substance that has an affinity

Chemical affinity

In chemical physics and physical chemistry, chemical affinity can be defined as electronic properties by which dissimilar chemical species are capable of forming chemical compounds....
to the substrate to which it is being applied. The dye is generally applied in an aqueous solution

Aqueous solution

An aqueous solution is a solution in which the solvent is water. It is usually shown in chemical equations by appending to the relevant formula....
, and may require a mordant

Mordant

A mordant is a substance used to set dyes on fabrics by forming an insoluble compound with the dye. It may be used for dyeing fabrics, or for intensifying stains in cell or tissue preparations....
to improve the fastness of the dye on the fiber.

Both dyes and pigments appear to be colored because they absorb some wavelengths of light

Light

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Encyclopedia

A dye can generally be described as a color

Color

Color or colour is the visual perception property corresponding in humans to the categories called red, yellow, blue and others....
ed substance that has an affinity

Chemical affinity

Aqueous solution

An aqueous solution is a solution in which the solvent is water. It is usually shown in chemical equations by appending to the relevant formula....
, and may require a mordant

Mordant

Light

Pigment

A pigment is a material that changes the color of light it Reflection as the result of selective color absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which the material itself emits light....
generally is insoluble, and has no affinity for the substrate. Some dyes can be precipitated

Precipitation (chemistry)

Precipitation is the formation of a solid in a solution during a chemical reaction. When the reaction occurs, the solid formed is called the precipitate, and the liquid remaining above the solid is called the supernate....
with an inert salt to produce a lake pigment

Lake pigment

A Lake pigment is a pigment manufactured by precipitating a dye with an inert binder, usually a metallic salt. Manufacturers and suppliers to artists and industry frequently omit the lake designation in the name....
, and based on the salt used they could be aluminum lake, calcium lake or barium lake pigments.

Archaeological

Archaeology

Archaeology, archeology, or arch?ology is the science that studies Homo cultures through the recovery, documentation, analysis, and interpretation of material remains and environmental data, including architecture, Artifact , features, Biofact s, and cultural landscape....
evidence shows that, particularly in India

India

India, officially the Republic of India , is a country in South Asia. It is the List of countries and outlying territories by total area country by geographical area, the List of countries by population country, and the most populous liberal democracy in the world....
and the Middle East

Middle East

File:GreaterMiddleEast1.pngThe Middle East is a region that spans southwestern Asia, western Asia, and northeastern Africa. It has no clear boundaries, often used as a synonym to Near East, in opposition to Far East....
, dyeing has been carried out for over 5000 years. The dyes were obtained from animal

Animal

Animals are a major group of multicellular, eukaryotic organisms of the Kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life....
, vegetable

Vegetable

The term "vegetable" generally means the Eating parts of plants. The definition of the word is traditional rather than scientific, however, and therefore the usage of the word is somewhat arbitrary and subjective, as it is determined by individual cultural customs of food selection and food preparation....
or mineral

Mineral

A mineral is a naturally occurring solid formed through Geology processes that has a characteristic chemical composition, a highly ordered atomic structure, and specific physical properties....
origin, with no or very little processing. By far the greatest source of dyes has been from the plant kingdom, notably root

Root

In vascular plants, the root is the organ of a plant body that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial root or aerating ....
s, berries

Berry

In everyday English, a berry is a broad term for any small edible fruit. Most berries are juicy, round or semi-oblong, brightly coloured, sweet or sour, and don't have a stone or pit....
, bark

BARK

BARK was an early Electromechanics. BARK was built using standard phone relays, implementing a 32-bit binary machine and could perform addition in 150 ms and multiplication in 250 ms....
, leaves

Leaf

In botany, a leaf is an above-ground plant Organ specialized for photosynthesis. For this purpose, a leaf is typically flat and thin, to expose the cells containing chloroplast to light over a broad area, and to allow light to penetrate fully into the tissues....
and wood

Wood

Wood is an organic material; in the strict sense wood is produced as secondary xylem in the stems of woody plants, notably trees but also shrubs, etc....
, but only a few have ever been used on a commercial scale.

Organic dyes

The first human-made (synthetic) organic

Organic compound

An organic compound is any member of a large class of chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of compounds such as carbonates, simple oxides of carbon and cyanides, as well as the allotropes of carbon, are considered Inorganic compound....
dye, mauveine

Mauveine

Mauveine, also known as aniline purple and Perkin's mauve, was the first synthetic organic chemistry dye.Its chemical name is3-amino-2,?9-dimethyl-5-phenyl-7-phenazinium acetate....
, was discovered by William Henry Perkin in 1856. Many thousands of synthetic dyes have since been prepared.

Synthetic dyes quickly replaced the traditional natural dyes. They cost less, they offered a vast range of new colors, and they imparted better properties upon the dyed materials. Dyes are now classified according to how they are used in the dyeing process.

Acid dye
Acid dye

Acid dye is a member of a class of dye that is applied from an acidic solution. In the home or art studio, the acid used in the dyebath is often vinegar or citric acid....
s are water

Water

Water is a common chemical substance that is essential for the survival of all known forms of life. In typical usage, water refers only to its liquid form or States of matter, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam....
-soluble anionic

Anionic

In chemistry, an anionic species is one that contains a full electric charge. These types of chemical compound can range in reactivity, but most are fairly reactive.Anionic is a chemical that is also used in things like washing detergent.......
dyes that are applied to fiber

Fiber

Fiber or fibre is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of yarn. They are very important in the biology of both plants and animals, for holding tissue s together....
s such as silk

Silk

Silk is a natural protein fiber, some forms of which can be weaving into textiles. The best-known type of silk is obtained from Pupa#Cocoons made by the larvae of the mulberry silkworm Bombyx mori reared in captivity ....
, wool

Wool

Wool is the fiber derived from the specialized skin cells, called follicles, of animals in the Caprinae family, principally domestic sheep, but the hair of certain species of other Mammalia such as cashmere goat, llamas, rabbits and keeshonds may also be called wool....
, nylon

Nylon

Nylon is a generic designation for a family of synthetic polymers known generically as polyamides and first produced on February 28, 1935 by Wallace Carothers at DuPont....
and modified acrylic fiber

Acrylic fiber

Acrylic fibers are synthetic fibers made from a polymer with an average molecular weight of ~100,000, about 1900 monomer units. To be called acrylic in the U.S, the polymer must contain at least 85% acrylonitrile monomer....
s using neutral to acid dyebaths. Attachment to the fiber is attributed, at least partly, to salt formation between anionic groups in the dyes and cationic groups in the fiber. Acid dyes are not substantive to cellulosic

Cellulose

File:Cellulose Sessel.svgCellulose is an organic compound with the chemical formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand ? linked D-glucose units....
fibers. Most synthetic food colors fall in this category.

Basic dyes are water-soluble cationic dyes that are mainly applied to acrylic fiber

Acrylic fiber

Acetic acid

Acetic acid, CH3COOH, also known as ethanoic acid, is an organic acid which gives vinegar its sour taste and pungent smell. Pure, water-free acetic acid is a colourless liquid that absorbs water from the environment , and freezes at 16.7 Celsius to a colourless crystalline solid....
is added to the dyebath to help the uptake of the dye onto the fiber. Basic dyes are also used in the coloration of paper

Paper

Paper is thin material mainly used for writing upon, printing upon or packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....
.

Direct or substantive dye
Substantive dye

Substantive dye is a dye used in a process in which dye molecules are attracted by physical forces at the molecular level to the textile. The amount of this attraction is known as "substantivity": the higher the substantivity the greater the attraction of the dye for the fiber....
ing is normally carried out in a neutral or slightly alkaline dyebath, at or near boiling point

Boiling point

The boiling point of a liquid is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid....
, with the addition of either sodium chloride

Sodium chloride

Sodium chloride, also known as common salt, table salt, or halite, is a chemical compound with the chemical formula SodiumChlorine....
(NaCl) or sodium sulfate

Sodium sulfate

Sodium sulfate is the sodium salt of sulfuric acid. Anhydrous, it is a white crystalline solid of formula Na2SO4 known as the mineral thenardite; the hydrate Na2SO4?10H2O has been known as Glauber's salt or, historically, sal mirabilis since the 17th century....
(Na₂SO₄). Direct dyes are used on cotton

Cotton

Cotton is a soft, staple fiber that grows in a form known as a boll around the seeds of the cotton plant a shrub native to tropical and subtropical regions around the world, including the Americas, India and Africa....
, paper, leather

Leather

Leather is a material created through the tanning of rawhides and skins of animals, primarily cattlehide. The tanning process converts the putrescible skin into a durable, long-lasting and versatile natural material for various uses....
, wool, silk and nylon

Nylon

PH indicator

A pH indicator is a halochromism chemical chemical compound that is added in small amounts to a solution so that the pH of the solution can be determined easily....
s and as biological stain

Staining (biology)

Staining is an auxiliary technique used in microscopy to enhance contrast in the microscopic image.In biochemistry it involves adding a class-specific dye to a substrate to qualify or quantify the presence of a specific compound....
s.

Mordant dyes require a mordant

Mordant

A mordant is a substance used to set dyes on fabrics by forming an insoluble compound with the dye. It may be used for dyeing fabrics, or for intensifying stains in cell or tissue preparations....
, which improves the fastness of the dye against water, light

Light

Light, or visible light, is electromagnetic radiation of a wavelength that is Visible spectrum to the human eye , or up to 380?750 nm. In the broader field of physics, light is sometimes used to refer to electromagnetic radiation of all wavelengths, whether visible or not....
and perspiration. The choice of mordant is very important as different mordants can change the final color significantly. Most natural dyes are mordant dyes and there is therefore a large literature base describing dyeing techniques. The most important mordant dyes are the synthetic mordant dyes, or chrome dyes, used for wool; these comprise some 30% of dyes used for wool, and are especially useful for black and navy shades. The mordant, potassium dichromate

Potassium dichromate

Potassium dichromate, K2Cr2O7, is a common inorganic compound chemical reagent, most commonly used as an oxidizing agent in various laboratory and industrial applications....
, is applied as an after-treatment. It is important to note that many mordants, particularly those in the heavy metal category, can be hazardous to health and extreme care must be taken in using them.

Vat dye
Vat dye

Vat dyes are an ancient class of dyes, based on the natural dye, indigo, which is now produced synthetically....
s are essentially insoluble in water and incapable of dyeing fibres directly. However, reduction in alkaline liquor produces the water soluble alkali

Alkali

In chemistry, an alkali is a Base , Ionic compound salt of an alkali metal or alkaline earth metal Chemical element. Alkalis are best known for being Base s that dissolve in water....
metal

Metal

In chemistry, a metal is a chemical element whose atoms readily lose electrons to form positive ions , and form metallic bonds between other metal atoms and ionic bonds between nonmetal atoms....
salt

Salt

A salt, in chemistry, is defined as the product formed from the neutralisation reaction of acids and base . Salts are ionic compounds composed of cations and anions so that the product is electrically electric charge ....
of the dye, which, in this leuco form, has an affinity for the textile fibre. Subsequent oxidation reforms the original insoluble dye. The color of denim is due to indigo, the original vat dye.

Reactive dyes utilize a chromophore

Chromophore

A chromophore is part of a molecule responsible for its color.When a molecule absorbs certain wavelengths of visible spectrum and transmits or reflects others, the molecule has a color....
attached to a substituent

Substituent

In organic chemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon. The suffix -yl is used when naming organic compounds that contain a substituent....
that is capable of directly reacting

Chemical reaction

A chemical reaction is a process that always results in the interconversion of chemical substances. The substance or substances initially involved in a chemical reaction are called reactants....
with the fibre substrate. The covalent bonds that attach reactive dye to natural fibers make them among the most permanent of dyes. "Cold" reactive dyes, such as Procion MX, Cibacron F, and Drimarene K, are very easy to use because the dye can be applied at room temperature. Reactive dyes are by far the best choice for dyeing cotton

Cotton

Cellulose

File:Cellulose Sessel.svgCellulose is an organic compound with the chemical formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand ? linked D-glucose units....
fibers at home or in the art studio.

Disperse dyes were originally developed for the dyeing of cellulose acetate

Cellulose acetate

Cellulose acetate, first prepared in 1865, is the acetate ester of cellulose. Cellulose acetate is used as a film base in photography, and as a component in some adhesives; it is also used as a synthetic fiber....
, and are substantially water insoluble. The dyes are finely ground in the presence of a dispersing agent and then sold as a paste, or spray-dried and sold as a powder. Their main use is to dye polyester

Polyester

Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate ....
but they can also be used to dye nylon, cellulose triacetate

Cellulose triacetate

Cellulose triacetate, also known simply as triacetate, is manufactured from cellulose and acetate. Triacetate is typically used for the creation of fibres and film base....
, and acrylic fibres. In some cases, a dyeing temperature

Temperature

In physics, temperature is a physical property of a Physical system that underlies the common notions of hot and cold; something that feels hotter generally has the greater temperature....
of 130 °C

Celsius

Celsius is a temperature scale that is named after the Swedish astronomer Anders Celsius , who developed a similar temperature scale two years before his death....
is required, and a pressurised dyebath is used. The very fine particle size gives a large surface area that aids dissolution to allow uptake by the fibre. The dyeing rate can be significantly influenced by the choice of dispersing agent used during the grinding.

Azo dyeing is a technique in which an insoluble azoic dye is produced directly onto or within the fibre. This is achieved by treating a fibre with both diazoic and coupling component

Component

A component is any smaller, self-contained part of a larger entity....
s. With suitable adjustment of dyebath conditions the two components react to produce the required insoluble azo dye. This technique of dyeing is unique, in that the final color is controlled by the choice of the diazoic and coupling components.

Sulfur dye
Sulfur dye

Sulfur dyes are the most commonly used dyes manufactured for cotton in terms of volume. They are cheap, generally have good wash-fastness and are easy to apply....
s are two part "developed" dyes used to dye cotton with dark colors. The initial bath imparts a yellow or pale chartreuse

Chartreuse

Chartreuse may refer to:* Chartreuse , a family of colors between yellow and green* Chartreuse , a brand of liqueur produced in Voiron, France, near the Grande Chartreuse monastery...
color, This is aftertreated with a sulfur compound in place to produce the dark black we are familiar with in socks for instance. Sulfur Black 1 is the largest selling dye by volume.

Food dyes

One other class which describes the role of dyes, rather than their mode of use, is the food dye

Food coloring

A food coloring is any substance that is added to food or drink to change its color. Food coloring is used both in commercial food production and in domestic cooking....
. Because food dyes are classed as food additive

Food additive

Food additives are substances added to food to preserve flavour or improve its taste and appearance.Some additives have been used for centuries; for example, preserving food by pickling , edible salting, as with bacon, preserving sweets or using sulfur dioxide as in some wines....
s, they are manufactured to a higher standard than some industrial dyes. Food dyes can be direct, mordant and vat dyes, and their use is strictly controlled by legislation

LAW

LAW may refer to:* Anti-tank warfare, e.g. the US Army M72 LAW or the British Army LAW 80*Palestinian Society for the Protection of Human Rights ...
. Many are azoic dyes, although anthraquinone

Anthraquinone

Anthraquinone is an aromatic hydrocarbon organic compound. It is a derivative of anthracene. It has the appearance of yellow or light gray to gray-green solid crystalline powder....
and triphenylmethane

Triphenylmethane

Triphenylmethane, or triphenyl methane, is the hydrocarbon with the chemical formula 3CH. This colorless solid is soluble in nonpolar organic solvents, but not water....
compounds are used for colors such as green

Green

Green is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520?570-Nanometre....
and blue

Blue

Blue is a colour, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 440?490 Nanometre....
. Some naturally-occurring dyes are also used.

Other important dyes

A number of other classes have also been established, including:

Oxidation bases, for mainly hair and fur
Leather
Leather

Leather is a material created through the tanning of rawhides and skins of animals, primarily cattlehide. The tanning process converts the putrescible skin into a durable, long-lasting and versatile natural material for various uses....
dyes, for leather
Fluorescent brighteners, for textile fibres and paper
Solvent dye
Solvent dye

A solvent dye is a dye soluble in organic solvents. It is usually used as a solution in an organic solvent.Solvent dyes are used to color organic solvents, hydrocarbon fuels, waxes, lubricants, plastics, and other hydrocarbon-based nonpolar materials....
s, for wood staining and producing colored lacquers, solvent inks, coloring oils, waxes.
Carbene dye
Carbene dye

A carbene dye is a reactive dye based on carbene chemistry.A benzophenone is functionalised with a chromophore or group that can be easily converted to a chromophore at a later stage....
s, a recently developed method for coloring multiple substrates

Chemical classification

By the nature of their chromophore

Chromophore

Category:Acridine dyes, derivates of acridine

Acridine

Acridine, C13H9N, is an organic compound and a heterocyclic compound. Acridine is also used to describe compounds containing the C13N tricycle....

Category:Anthraquinone dyes, derivates of anthraquinone

Anthraquinone

Anthraquinone is an aromatic hydrocarbon organic compound. It is a derivative of anthracene. It has the appearance of yellow or light gray to gray-green solid crystalline powder....

Arylmethane dyes
Category:Diarylmethane dyes, based on diphenyl methane
Category:Triarylmethane dyes, derivates of triphenyl methane

Category:Azo dyes, based on -N=N- azo

Azo compound

Azo compounds are chemical compound bearing the functional group R-N=N-R', in which R and R' can be either aryl or alkyl. The N=N group is called an azo group, although the parent compound, HNNH, is called diimide....
structure

Cyanine dyes, derivates of phthalocyanine
Phthalocyanine

A phthalocyanine is a macrocycle having an alternating nitrogen atom-carbon atom ring structure .The molecule is able to coordinate hydrogen and metal cations in its center by coordinate bonds with the four isoindole nitrogen atoms....
Diazonium dyes, based on diazonium salts
Nitro dyes, based on a -NO₂ nitro functional group
Nitroso dyes, based on a -N=O nitroso
Nitroso

Nitroso refers to a functional group in organic chemistry which has the general formula RNO. Nitroso compounds can be prepared by the reduction of nitro compounds or by the oxidation of hydroxylamines....
functional group
Phthalocyanine dyes, derivates of phthalocyanine
Phthalocyanine

A phthalocyanine is a macrocycle having an alternating nitrogen atom-carbon atom ring structure .The molecule is able to coordinate hydrogen and metal cations in its center by coordinate bonds with the four isoindole nitrogen atoms....
Quinone-imine dyes, derivates of quinone
Quinone

Quinones are "compounds having a fully conjugated cyclic Diketone structure, such as that of benzoquinones, derived from aromatic compounds by conversion of an even number of ?CH= groups into ?C? groups with any necessary rearrangement of double bonds ."...

Category:Azin dyes
:Category:Eurhodin dyes
:Category:Safranin dyes, derivates of safranin
Safranin

Safranin is a staining used in histology and cytology. Safranin is used as a counterstain in some staining protocols, colouring all cell nucleus red....

Indamins
Category:Indophenol dyes, derivates of indophenol
Category:Oxazin dyes, derivates of oxazin
Oxazone dyes, derivates of oxazone
Nile red

Nile red is a hydrophobic stain. It is produced by boiling a solution of Nile blue with sulfuric acid. As can be seen from the structural formulae, this process replaces an amino group with a carbonyl group....

Category:Thiazin dyes, derivates of thiazin

Category:Thiazole dyes, derivates of thiazole

Thiazole

Thiazole, or 1,3-thiazole, is a clear to pale yellow flammable liquid with a pyridine-like odor and the molecular formula C3H3NS....

Xanthene dyes, derived from xanthene
Xanthene

Xanthene is a yellow organic compound heterocyclic compound. Its chemical formula is 1310. It is soluble in diethyl ether....

Fluorene dyes, derivates of fluorene
Fluorene

Fluorene, or 9H-fluorene, is a polycyclic aromatic hydrocarbon. It forms white crystals that exhibit a characteristic, aromatic odor similar to that of naphthalene....

Pyronin dyes
Category:Fluorone dyes, based on fluorone
Fluorone

Fluorone is the basic skeleton for various chemicals, most notably fluorone dyes ....

:Category:Rhodamine dyes, derivates of rhodamine
Rhodamine

Rhodamine is a family of related chemical compounds, fluorone dyes. Examples are Rhodamine 6G and Rhodamine B. They are used as a dye and as a dye laser gain medium....

Dye

Organic dyes

Food dyes

Other important dyes

Chemical classification

See also

External links