Dyeing

In the carpet industry, dyeing plays an extremely important role as without colours no design can be created. The dyer is a central figure, and often somewhat mysterious, since the secrets of dyeing are closely held and passed on from one generation to another. This mystique is today less pronounced in urban centres but the dyer is nevertheless a figure of considerable importance and prestige.

Persian dyers, over centuries, have created a wide range of colours by combining various basic colours. With the analysis of light in a crystal prism, seven colours like those in a rainbow, i.e., violet, indigo, blue, green, orange and red are formed.

In this collection of colours, yellow, red and blue are called the principal colours while violet, green and orange are the complementary ones. With a combination of these colours in different proportions, an exciting world of colours is formed.

For instance, various shades of green are obtained from a mixture of yellow and blue. Various kinds of orange colours are obtained from the combination of yellow and red. Thus a variety of colours can be obtained.

The colours can be basically divided into two broad categories: Natural dyes and artificial dyes.

Natural dyes

Often referred to as vegetable dyes, though many of these were obtained from animal and mineral sources. Despite the introduction of good quality synthetic dyes, which are reasonably cheap and plentiful the master dyers in Iran prefer the use of natural dyes. Natural dyes produce a subtle beauty of tone that has never been equalled by use of even the finest synthetic dyes. The natural dyes come from roots, flowers, leaves, fruits and barks of plants, or from animal sources such as cochineal and or mineral sources such as red soils. The natural dyes had the advantage of being found in abundance in the natural environments. Red is obtained from the roots of the madder plant (Rubia tinctorum) and also from the crushed bodies of female insects of the coccus cacti genus. Yellow is made from the reseda plant, vine leaves and pomegranate skins. Blue is derived from Indigo plants... Iranians are reputed to have had a long history of developing these natural dyes that were fast and attractive. Plutorch, the famous historian, while describing the victories of Alexander of Macedonia talks of the purple coloured fabrics which were looted by his soldiers and writes: ‘the fastness of the colours and the durability of the fabrics woven in Iran are due to the fact that they made use a mixture of honey and wax About 120 different kind of coloured plants have been identified in Iran. From the leaves, bark, roots, flowers and fruits of this plant, various colours are obtained. Additionally some natural dyes are extracted from lichens and alga.

These lichens grow in the damp soil near the sea, in forests and on the rocks.

These are collected and then dried, before being used as dyes. With a combination of substances derived from these lichens and various mordants, different shades of colours like brown, yellow and orange are obtained.

Mordants

In the dyeing terminology mordants are substances used to improve the absorption of colours by the outer surface of the wool and ensure fastness of the colours, when exposed to sunlight or water. The outer surface of the wool has a characteristic of being waterproof and thus resistance to colour absorption. Use of special chemical substance considerably reduces and even eliminates this colour resistance layer and improves the darkness and lightness of the dye. Therefore, as a first step, the wool is treated with mordants, before it is immersed in the dyeing tanks.

The principal sources of natural colours

Safflower ( Golrangh)

Scientific name of this plant is “Carthamus Tinctorius L.” and in Iran it is popularly known as golrangh. The plant grows up to the height of one metre. Its leaves are thorny and shiny. The flowers of this plant are initially Saffron colour, which later turn red. The Iranian dyers use the petals to dye the silk fibre to a golden red.

Madder (Ronas)

The botanical name of this plant is “rubia Tinctorum” but the variety of this plant that grows in Iran called Rubia Peregrina. The plant is cultivated in areas of Azarbaijan, Mazandarän, Kerman and in some central parts of Iran. It produces natural red colours. The root of this plant grows a depth of two metres or so in sandy soil, from which one gets a better colour essence. The plant root has a substance named “Rabitric acid” composed of sugar and colour essence called Alizarin. To produce the red colour, the root is taken out in late autumn and dried in the sun or in special furnaces (60 Degree Centigrade). However, the best colour is obtained, if it is dried in the shade. In the dyeing process Iranian dyers generally use sour milk which contains lactic acid. By use of this process they obtain fast and shiny colour.

Cochineal ( Ghermez Daneh)

The scientific name “Coctu cacti”. The existence and use of this insect has been known for a long time for preparing natural red colours. The red substance which is a compound of “carminic acid” oozes out of the body of this insect. The insect developed on the shores of the Persian Gult and Sea of Oman and in parts of Baluchestan. The various species of Cochineal live on the Oak and cactus trees and they increase with such rapidity that they cover all the branches.

Saffron (Zaferan)

Botanical name ‘Crocus Sativus” is a bulbous plant.

It is cultivated in Ghaenat and Birjand area of Khorasan province of Iran. Highly valued for its taste and flavour it is used to improve the quality of food.

On account of its world wide demand, the price had a phenomenal increase; therefore, it is no longer used as dye.

Logwood (Bagham)

Botanical name “Haematoxylon Campechianum”. It is a thorny tree. Its bark is boiled and the sap obtained from it is transformed into powder or crystallised form.

It is then used for dyeing natural black and grey colours.

Exposure to sunlight does not effect the colours produced from logwood. Together with different mordants logwood produced light purple, violet, grey and black colours. For obtaining pure black colour, Iranian dyers use a mixture of a logwood and Esparak.

Indigo (Nil)

The botanical name is “Indigofea Tinctoria’. Originally the plant was found in India from where it had been taken to different parts of the world.

Mankind has known the Indigo bush for a long time. It was cultivated to produce blue and green colours. In Iran it was cultivated in Khuzestan and in the Southern Regions. With the development of artificial Indigo, the cultivation of Indigo plant has been reduced. There are the several varieties of indigo plant but these all contain one or two colour substances. When the leaves of this plant are crushed, a green substance oozes out and as soon as it gets in contact with air, the colours transferred to blue.

Indigo is one of the best natural dyes. It resist washing as well as rubbing and the colour stays solid and fast.

Dye, Weed (Esparak)

Botanical name “Reseda Luteola’. It is a biennal plant. It produces yellow colour. It grows wild and in abundance in Iran. Due to continuous exposure to light the dye from this plant gives fast yellow colour for many years. This dye has been extensively used in Iran.

Despite easy availability of chemical dyes, Reseda has not lost its place with the dyers in Iran and continues to be extensively used.

The Esparak plant is also cultivated. All parts of the plant contain colouring substances but the root and upper sections of the bush especially the flower give the best colour.

Turmeric (Zardchubeh)

Botanical name “Curcuma Longa”. From the rootstalk, ordinary turmeric is obtained. Is it mostly used in cooking and grows in plenty in Iran. turmeric, when used with different mordants in the dyeing process produces several varieties of brown, dark, grey, greenish yellow and orange.

Plants containing Tannin

Pomegranate (Anar)

Botanical name “Punica Granatum’ was first grown in Iran and is today found in various parts of the world. The skin of its fruit is used for dyeing and grey and dark colours are obtained, it is used more than other plants containing tannin.

The quantity of Tannin substance in Pomegranate is up to 40%.

Oak-Tree (Balut)

The scientific name “Quercus Tinctoria”. From the trunk, branches, bark of this tree are extracted large quantities of tannin substance which are used for medicinal, tannery and dyeing purposes. the tannin substances contained in the bark of the Oak-tree with different mordants produce yellow-orange and brown colours. 

Walnut (Gherdu) 

Botanical name “junglans Regia”. Walnut trees are found in abundance in areas of Iran having a moderate climate. The nutshell of this plant contains tannin 35-40%. with use of different mordants the tannin in the shell produces brown and dark colours.

Mirabalan (Halileh) 

Botanical name ‘Prunus Cerasifera Myrabolana” resembles a plum and is dried before it matures. It has around 45% of tannin. Apart from dyeing, it is also used for medicinal purposes. Two varieties of this plant are in existence. “Yellow Myrabolan”. From which yellow colours is obtained and black Myrabolan, from which black and green colours are obtained by use of different mordants. 

Other colour plants

The leaves of mulberry, vine, henna and plane trees are commonly used for the development of natural dyes, white mulberry gives yellow; black mulberry and its fruit, violet; red and greyish colours are obtained with use of different mordants.

The leaves of the vine give olive green when brought in contact with galvanised iron and almost orange when treated with alkaline salts. Light and dark green colours are produced from plane tree leaves. Wool when boiled with corn straw gives light beige; if boiled with onion skin, it becomes pink; and with henna leaves, it gives a jasper green colour.

Synthetic dyes

With the expansion of textile and carpet weaving industries, a need was felt for producing chemical dyes, which would be cheaper, readily available and could give a variety of colours. These synthetic dyes were introduced in Persia and Anatolia in the later half of the 19 century. The first dye discovered by Perkins, appeared in the market in 1856. Following this, in 1869, two German scientists Graebe and Liebermann, produced the compound of Alizarine (a colouring substance present in the root of madder plant). In 1897, artificial Indigo, was discovered by German chemist Bayer and offered commercially in the market. These synthetic dyes proved unsuitable for carpet yarns as these produced crude colours that were given to rapid fading. The fading of some chemical dyes when in contact with light or water created an unfavourable impression and made some believe that all synthetic dyes react similarly when faced with these unfavourable elements. In reality except for Aniline colours other synthetic dyes when compared with the natural dyes, often show a stronger reaction to light and water.

In 1903 the Persian government enforced strict laws, prohibiting use of these dyes. These measures proved effective, and Persian weavers went back to using natural dyes until the more reliable chrome dyes appeared on the market around 1920.

Over the period of the last 50 years or so, dyes there are of reliable colour-fast and made in a wide range of colours and shades have appeared on the world market.

Assured of the permanence and fastness of these dyes, the Persian rug weavers are now using extensively these chrome-based dyes, along with the natural dyes.

Abrash

An unexpected colour variation in the field of a carpet is called an “abrash”.

Once in a while it is pleasant and charming to see this harsh and sharp shade difference, which in some carpets extends to a certain length and in some others all throughout the length of the carpet. The reason for the striped irregularity of abrash is due to the alterations in the dyeing process of skeins of wool and the use of mordants. This change occurs mostly in nomadic or tribal as the lack of means of these people causes them to buy and dye the hanks of wool at different times and from various lots in small quantities whereas in big carpet workshops the skeins of dye lots are supplied in large quantities.

Making carpets look old

Over the years and as a result of wear and tear the carpet loses its scales and begins to show its age.

Years ago in Iran to make a carpet look old and to eliminate its raw and sharp colours, it was the custom to spread the carpets in the streets and markets so as to be walked on by the passers by or the carpets were spread under the sun and washed with water to which “chubak” a kind of soapy root ashes which contain alkaline were added.

This process can also be made with Hipochioride, commercially known as a whitesmith powder, because when immersed in chloric salts the wool loses its scales.

To give more importance to the originality and antiquity, the merchants normally apply the process of chemical washing to carpets that are destined for exportation, new methods and tests ascertain the age of fibres and the dyes used. Even the date of texture of some carpets which have been copied from works done in the sixteenth and seventeenth centuries and attributed to that era can be verified.