What Is Dye

A dye can generally be described as a colored substance that has an affinity to the substrate to which it is being applied. The dye is usually used as an aqueous solution and may require a mordant to improve the fastness of the dye on the fiber. (In contrast, a pigment generally has no affinity for the substrate, and is insoluble). A mordant is a substance used to set dyes. A mordant is either inherently colloidal or produces colloids and can be either acidic or basic. Mordants include tannic acid, alum, chrome alum, and certain salts of aluminum, chromium, copper, iron, iodine, potassium, and tin. 

Archaeological evidence shows that, particularly in India and the Middle East, dyeing has been carried out for over 5000 years. The dyes were obtained from either animal, vegetable or mineral origin with no or very little processing. By far the greatest source of dyes has been from the plant kingdom, notably roots, berries, bark, leaves and wood, but only a few have ever been used on a commercial scale.

Natural Dyes

Inorganic Dyes

The first man made organic dye, mauveine, was discovered by William Henry Perkin in 1856. Many thousands of dyes have since been prepared and because of vastly improved properties imparted upon the dyed materials quickly replaced the traditional natural dyes. Dyes are now classified according to how they are used in the dyeing process.

Acid Dye
Water soluble anionic dyes that are applied to fibers such as silk, wool, nylon and modified acrylic fibers from neutral to acid dye baths. 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 cellulose fibers.

Basic Dye
Water soluble cationic dyes that are mainly applied to acrylic fibers but find some use for wool, and silk. Usually acetic acid is added to the dye bath to help the take up of the dye onto the fiber. Basic dyes are also used in the coloration of paper.

Direct (Substantive) Dye
Dyeing is normally carried out in a neutral or slightly alkaline dye bath, at or near the boil, with the addition of either sodium chloride (NaCl) or sodium sulphate (Na2SO4). Direct dyes are used on cotton, paper, leather, wool, silk and nylon. They are also used as pH indicators and as biological stains.

Mordant Dye
As the name suggests these dyes require a mordant. This improves the fastness of the dye on the fiber such as water, light and perspiration fastness. 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 (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 used is potassium dichromate applied as an after-treatment.

Vat Dye
These dyes are essentially insoluble in water and incapable of dyeing fibers directly. However, reduction in alkaline liquor produces the water soluble alkali metal salt of the dye. In this leuco form these dyes have an affinity for the textile fiber. Subsequent oxidation reforms the original insoluble dye.

Reactive Dye
First appeared commercially in 1956, after their invention in 1954 by Rattee and Stephens at the ICI Dyestuffs Division site in Blackley, Manchester, UK. They are used to dye cellulose fibers. The dyes contain a reactive group, either a haloheterocycle or an activated double bond, that, when applied to a fiber in a weakly alkaline dye bath, forms a chemical bond with an hydroxyl group on the cellulose fiber. Reactive dyeing is now the most important method for the coloration of cellulose fibers. Reactive dyes can also be used to dye wool and nylon, in the latter case they are applied under weakly acidic conditions.

Disperse Dye
Originally developed for the dyeing of cellulose acetate. They are substantially water insoluble. The dyes are finely ground in the presence of a dispersing agent then sold as a paste or spray dried and sold as a powder. They can also be used to dye nylon, triacetate, polyester and acrylic fibers. In some cases a dyeing temperature of 130 deg C is required and a pressurized dye bath is used. The very fine particle size gives a large surface area that aids dissolution to allow uptake by the fiber. The dyeing rate can be significantly influenced by the choice of dispersing agent used during the grinding.

Azoic Dye
A dyeing technique in which an insoluble azo dye is produced directly onto or within the fiber. This is achieved by treating a fiber with a diazo component and a coupling component. With suitable adjustment of dye bath 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 diazo and coupling components.

Food Dyes
This is a special class of dyes of very high purity. They include direct, mordant and vat dyes. Their use is strictly controlled by legislation. Many are azo dyes but anthraquinone and triphenylmethane compounds are used for colors such as green and blue. Some naturally occurring dyes are also used.

Dyeing is the process of changing the color of a yarn or cloth by treatment with a dye.

For the majority of the thousands of years in which dyeing has been used by man to decorate clothing, or fabrics for other uses, the primary source of dye has been nature, with the dyestuff being extracted from animals or plants. In the last two centuries, man has produced artificial dyes to achieve specific colors, and to render the dyes 'fast', so that they do not run when the material is washed.

Dyes are applied to material by direct application, or by immersing the yarn or cloth in the liquid dye or a solution of the dye. In order to remove natural or unwanted color from material, the opposite process of bleaching is carried out.

Dyeing Techniques

Tie-dye is method of dyeing clothing popularized by members of the hippie subculture. Clothes are tied, either with string or rubber bands into some sort of pattern. Then the clothes are dyed, either by submerging them or by squirting dye solution onto them. Where the fabric is tied, some areas do not absorb dye, forming a pattern. This is known as a resist technique (the areas that are tied resist dyeing).

Shibori is a form of tie-dye which originated in Japan, which has been practiced there since at least the eighth century. Shibori includes a number of labor-intensive resist techniques including stitching elaborate patterns and tightly gathering the stitching before dyeing, forming intricate designs for kimonos. Another shibori method is to wrap the fabric around a core of rope, wood or other material, and bind it tightly with string or thread. The areas of the fabric that are against the core or under the binding would remain un-dyed.

Plangi and tritik are Malay-Indonesian words for methods related to tie-dye, and banda is a term from India. Ikat is a method of tie-dying the warp or weft before the cloth is woven.

Ikat is a style of weaving that uses a tie-dye process on either the warp or weft before the threads are woven to create a pattern or design. A Double Ikat is when both the warp and the weft are tie-dyed before weaving.

"Ikat" means "tied" or "bound" in the Malay language which describes the process. Through common usage the word has come to describe both the process and the cloth itself. Ikats have been woven in cultures all over the world. In Central and South America Ikat is still common in Argentina, Bolivia, Ecuador, Guatemala and Mexico. India, Japan and several South-East Asia countries have cultures with long histories of Ikat production. Double Ikats can still be found in India, Guatemala, Japan and the Indonesian island of Bali.

Like any craft or art form, ikats vary widley from country to country and region to region. Designs may have symbolic of ritual meaning or have been developed for export trade. Ikats are often symbols of status, wealth, power and prestige. Perhaps because of the difficulty and time required to make ikats, some cultures believe the cloth is imbued with magical powers.

The History of Ikat
There are known links between Ikat production in India and South-East Asia. Patola cloth, a double ikat from Gujarat, western India, used to be exported to Indonesia for the use of the royal families. The patterns in the Patola Ikats are strikingly similar to the double ikats produced in Bali, Indonesia. Ancient trading routes linked India and South-East Asia and also linked Central Asia with India. Because woven fabric rarely survives for more than a few centuries it is extremely difficult, if not impossible, to determine where the technique of Ikat originated. It probably developed in several different locations independently. Ikat was known to be produced in several pre-Columbian Central and South American cultures.

How Ikat Is Made
Ikats created by dying the warp are the easiest to make. Before the warp strings are attached to the loom they are arranged into bundles. Each bundle is tied and dyed separately, so that a pattern will emerge when the loom is set up. This takes a good deal of skill. The tightly bound bundles are sometimes covered with wax or some other material that will keep the dyes from penetrating. The process is repeated several times for additional colors.

Some patterns have many strands in the cloth that are all dyed the same way which creates a blocky design. In some weaving traditions each strand of the cloth may be dyed differently from the ones next to it. Usually the pattern repeats in symmetrical or asymmetrical ways. In the illustration above, the right side of the weaving is identical to the left. To make these elaborate patterns the weaver will still bundle and dye several threads together, but when the loom is prepared, a single thread will be used from each bundle for each section of the pattern. Elaborate ikat patterns like this are often handed down from generation to generation in the same family.

After the threads are dyed the loom is set up. The pattern is visible to the weaver. Threads can be adjusted so that they line up correctly with each other. Some ikat styles (like in Japan and Guatemala) don't try to get the patterns precisely lined up, others (like in Timor in Indonesia) the patterns are so accurate, that you have to look closely to determine that the pattern was not printed on the cloth.

Dying the weft makes it much more difficult to make ikats with precise patterns. The weft is one continuous strand that is woven back and forth, so any errors in how the string is tied and dyed are cumulative. Because of this, weft ikats are usually used when the precision of the pattern is not the main concern. Some patterns become transformed by the weaving process into irregular and erratic designs.

Double ikats are the most difficult to produce. In the finest examples from India and Indonesia, the warp and the weft are precisely tied and dyed so that the patterns interlock and reinforce each other when the fabric is woven.

Batik is a wax-resist dyeing technique used on fabric. Batik is found in several countries. The island of Java in Indonesia is famous for its batik. Melted wax is applied to cloth before being dipped in dye. Wherever the wax has seeped through the fabric, the dye will not penetrate. Sometimes several colors are used, with a series of dyeing, drying and waxing steps.

Thin wax lines are made with a "canting", a tiny metal cup with a tiny spout, out of which the wax seeps. Other methods of applying the wax onto the fabric include pouring the liquid wax, painting the wax on with a brush, and applying the hot wax to a pre-carved wooden block and stamping the fabric.

After the last dyeing, the fabric is hung up to dry. Then it is dipped in a solvent to dissolve the wax, or ironed between paper towels or newspapers to absorb the wax and reveal the deep rich colors and the fine crinkle lines that give batik its character.

Procedure
Heat the wax in a tin can sitting in a pan of water. This makes sure the wax stays an even temperature and does not begin to smoke or burn.
Dry the fabric bone-dry before waxing or the wax will not penetrate the fabric.
Use cattle urea tablets to give the dye a real bite in the fabric. This produces rich colors. Some people use vinegar and salt instead.
Use paraffin wax if you want lots of crinkle lines. More beeswax if you want less crinkles.