Tie and dye requires fabric, dyes and lots of water. Some dyes require heating for preparation, while some are cold dyes. The fabrics used are cotton, silk, polyester, rayon, georgette, chiffon and linen. Sometimes wool is used as well. The dyes to be used with each of these materials differ with characteristics. Earlier, only natural dyes were used but with the coming of artificial fibers, the requirement for chemical dyes came up.
Dyes are used for coloring the fabrics. Dyes are molecules, which absorb and reflect light at specific wavelengths to give human eyes the sense of color. There are two major types of dyes - natural and synthetic dyes. The natural dyes are extracted from natural substances such as plants, animals, or minerals. Synthetic dyes are made in a laboratory. Chemicals are synthesized for making synthetic dyes. Some of the synthetic dyes contain metals too.
1) Natural Dyes It is the most common approach to apply a color pattern onto a fabric. If done on colored fabric, it is known as overprinting. Pressing dye on the fabric in a paste form produces the desired pattern. To prepare the print paste, a thickening agent is added to a limited amount of water and dye is dissolved in it. Earlier starch was preferred as a thickening agent for printing. Nowadays gums or alginates derived from seaweed are preferred as they allow better penetration of color and are easier to wash out. Most pigment printing is done without thickeners because the mixing up of resins, solvents and water produces thickening anyway.
2) Synthetic Dyes Synthetic dyes are classified based upon their chemical composition and the method of their application in the dyeing process.
3) Basic (Cationic) Dyes Basic (Cationic) Dyes are water-soluble and are mainly used to dye acrylic fibers. They are mostly used with a mordant. A mordant is a chemical agent which is used to set dyes on fabrics by forming an insoluble compound with the dye. With mordant, basic dyes are used for cotton, linen, acetate, nylon, polyesters, acrylics and mod acrylics. Other than acrylic, basic dyes are not very suitable for any other fiber as they are not fast to light, washing or perspiration. Thus, they are generally used for giving an after treatment to the fabrics that have already been dyed with acid dyes.
4) Direct (substantive) Dyes Direct dyes color cellulose fibers directly without the use of mordents. They are used for dyeing wool, silk, nylon, cotton, rayon etc. These dyes are not very bright and have poor fastness to washing although they are fairly fast to light.
5) Mordant Dyes The mordant or chrome dyes are acidic in character. Sodium or potassium dichromate is used with them in the dye bath or after the process of dyeing is completed. This is done for getting the binding action of the chrome. They are mostly used for wool, which gets a good color fastness after treatment with mordant dyes. They are also used for cotton; linen, silk, rayon and nylon but are less effective for them.
6) Vat Dyes Vat dyes are insoluble in water and cannot dye fibers directly. However, They can be made soluble by reduction in alkaline solution, which allows them to affix to the textile fibers. Subsequent oxidation or exposure to air restores the dye to its insoluble form. Indigo is the original vat dye. These dyes are the fastest dyes for cotton, linen and rayon. They are used with mordants to dye other fabrics such as wool, nylon, polyesters, acrylics and mod-acrylics.
7) Reactive Dyes Reactive dyes react with fiber molecules to form a chemical compound. These dyes, they are either applied from alkaline solution or from neutral solutions which are then alkalized in a separate process. Sometimes heat treatment is also used for developing different shades. After dyeing, the fabric is washed well with soap so as to remove any unfixed dye. Reactive dyes were originally used for cellulose fibers only but now their various types are used for wool, silk, nylon, acrylics and their blends as well.
8) Disperse Dyes Disperse dyes are water insoluble. These dyes are finely ground and are available as a paste or a powder that gets dispersed in water. These particles dissolve in the fibers and impart color to them. These dyes were originally developed for the dyeing of cellulose acetate but now they are used to dye nylon, cellulose triacetate, and acrylic fibers too.
9) Sulfur Dyes Sulfur Dyes are insoluble and made soluble by the help of caustic soda and sodium sulfide. Dyeing is done at high temperature with large quantities of salt so that the color penetrates into the fiber. After dyeing the fabric is oxidized for getting desired shades by exposure to air or by using chemicals. Excess dyes and chemicals are removed by thorough washing. These dyes are fast to light, washing and perspiration and are mostly used for cotton and linen.
10) Pigment Dyes Although pigments are not dyes in a true sense, they are extensively used for coloring fabrics like cotton, wool and other manmade fibers due to their excellent light fastness. They do not have any affinity to the fibers and are affixed to the fabric with the help of resins. After dyeing, the fabrics are subjected to high temperatures.
There is a lot of wastage of water and color from the dyes prepared for dyeing. Most of this being synthetic dyestuffs, makes the water unusable again, leading to permanent wastage and pollution of groundwater.
Tools & Technology
Measuring Equipment: To measure the dyestuffs is very important depending on the amount of fabric that needs to be dyed. To have accurate measurement for the same, different kinds of scales, weights, beakers and spoons are required.
Tongs: Tongs are required to lift the dyed fabric from the hot dye and dip it again and continue the same process till it is done.
Containers: Large containers are required to prepare the dyestuff in and also dye the fabric.
Stove: This is required to heat water and prepare the various synthetic dyes.
Drying wires: Drying wires are required to hang the dyed fabric for it to dry and fix the colours.
The process of making tie and dye work is quite simple, but also time-consuming. Over the years, the process of tie and dye has evolved and become more convenient. However, in certain parts of Rajasthan and Kutch, the traditional method is still followed. The method involves tightly tying the cloth at both ends. The area to be dyed is outlined with temporary colours. A thin sheet of plastic is then placed over the cloth. The plastic sheet has holes, and then using colours, an imprint is attained on the cloth. The craftsman then pulls every area where the holes were placed, to tie a knot. The thread used for tying the knot is usually nylon. After the knots are tied, the cloth is washed properly to remove any extra imprints, and then dipped in napthol for five minutes. The cloth is again dyed in a light colour for two minutes. Next, it is rinsed and dried, and again tied and dipped in a dark colour. The cloth is kept in the dark colour for three to four hours to form the background colour of the cloth. After this, the cloth is finally washed and dried and sometimes starched for the final finishing. After the fabric dries, the folds are pulled apart in a gentle manner to get rid of the knots, and reveal the final pattern. The final result is a dark coloured cloth, with contrasting light coloured dots in different patterns.