Dyes And Their Colourful Truths

The Colorful Truth About Dyes!!?

We all like to wear colourful clothes. Whether on a special occasion or just daily wear, it's always nice to add a little colour in our lives. Dyes are the chemical substances that are responsible for turning plain cloth into the colourful garments that we wear every day. 

What are dyes?

Dyes are substances applied in an aqueous based solutions to a fabric to give it colour. What makes a dye different from a pigment is that pigments are usually insoluble. 

Many methods of dyeing have been used in the history of humankind.using. Most of the dyes that we know are natural dyes found in the plant kingdom, available from a number of root, berries, bark, leaves and wood.



The structure of dyes..

You may have noticed that sometimes when you wash your clothes the colour seems to seep out of them. As a result when you dry your clothes, they seem to have become faded. Some dyes just stain fabrics and get washed away bit by bit whenever you wash your clothes. Good dyes on the other hand chemically attach themselves to the molecules of the fabric that you are dyeing. 

Different types of dyes molecules are all unique in their own way. Each is shaped differently so that it absorbs light in a different way. This results in the colour of the dye being different when it is processed in our eyes and brain. Often a third molecule is added to a dye. This acts as a bond between the dye molecule and the molecule of the fabric that the dye is being applied on.

The study of dyes made organic chemistry popular and it was one of the main reasons to the invention of drugs based on the chemical intermediates of dyes, like the invention of aspirin and sulfonamides.

                                                                             Synthetic dyes
Today there are a variety of synthetic dyes in use. These are more popular than natural dyes because of the wide range of colours that they offer and because they are cheaper and better than the natural ones. The first synthetic dye used, mauveine, was discovered in 1856 by a teenage boy named William Henry Perkin. He created this dye out of coal tar. 

Today synthetic dyes are classified by how they are used to dye fabrics. 

Acid dyes are highly reactive water soluble dyes that are used to colour fabrics like silk, wool and nylon. 

Mordant dyes use a substance that fixes the dye, making it resistant against water, light and perspiration. These dyes are usually used for colouring wool. 

Basic dyes are used with acetic acid to dye acrylic fibres. 

Vat dyes are not soluble in water and need to be reduced in alkaline liquor to get a water soluble, alkali metal salt of the dye. This can then be easily applied onto the fabric. When the fabric is subject to oxidation the original insoluble dye is reformed.

Disperse dyes are used to dye fabrics of polyester and are available as a paste or in the form of powder.

Sulfur dyes are the dyes that are used in large quantity. These dyes are applied in two part dyes. The first part produces a pale yellow colour while the second part uses a sulphur compound to produce dark shades and black.

Food dyes are classed as food additives, 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. Many are azo dyes, although anthraquinone and triphenylmethane compounds are used for colors such asgreen and blue. Some naturally-occurring dyes are also used.

Hair coloring is the practice of changing the color of hair. The main reasons for this practice are cosmetic such as to cover gray hair, to change to a color regarded as more fashionable or desirable, or to restore the original hair color after it has been discolored by hairdressing processes or sun bleaching. Hair dyeing, which is an ancient art, involves treatment of the hair with various chemical compounds. Today, hair coloring is immensely popular, with over 75 percent of American women dyeing their hair, and globally hair colorants are a rapidly growing over-$7 billion industry.



Why are dyes important?

Research in dyes are responsible for colour photography as well. In 1873 the German photo chemist Hermann Wilhelm Vogel added dyes to film that was only sensitive to blue and UV light, allowing the film to capture the colour green. By 1907 the French Lumiere brothers had perfected a colour process for the public called Autochrome. Today dyes are also widely used in printing, where the colours of cyan, yellow, magenta and black combine to form all the colours visuals that you see printed.