DYEING WITH NATURAL DYES

1. Introduction

S. P. MISHRA

Institute of Textile Technology,Choudwar – 754 025, Orissa

ABSTRACT

The knowledge and use of colour on textiles is one of the most important processes of fabric development and utilisation. The invention of synthetic dyes have replaced natural dyes and nearly stopped the use of natural dyes and colouring matters. In recent years, concern for the environment has created a deep interest in natural dyes. The present series on ‘Dyeing with Natural Dyes’ will highlight dyeing behaviour of some selected natural dyes.

1. INTRODUCTION :

Plants and plant products attracted the attention of mankind even in Ayurveda, when

practically the whole world was asleep in ignorance. The colour and the respective dyes find their

references in the Vedas and other religious scriptures. These dyes are oldest dyes and generally

referred as natural dyes. This means that, India has a rich tradition of using natural dyes and

India was the source of earliest natural dyes known to man 1. Natural dyes comprise those

colorants i.e., dyes and pigments that are obtained from animal or vegetable matter without

chemical processing. These dyes are supposed to be auspicious from the religious point of view 2.

These dyes can produce colour on cotton, wool, silk, etc. without any chemical

processing of the dyes. They are mainly mordant dyes, although some vat solvent, pigment,

direct and acid dyes are known. The colours are yellow, orange, pink, red, maroon, blue, brown,

purple and black. Color index lists 32 natural reds, 28 natural yellows, 6 natural orange, 12

natural brown, 5 natural green, 3 natural blue and 6 natural black 3. However, these dyes were

continuously neglected because of the synthetic dyes. Synthetic dyes have replaced almost all

the natural coloring matters. However, the art and craft of producing natural dyed textiles is being

practiced in every corner of the country by a handful of expert crafts-persons. This may be

Bandha Sarees in Orissa and Rajasthan, Multani sarees in Rajasthan, Gujrat and Madhya

Pradesh, Kalamkari Printing in Bihar and Andhra Pradesh 1.

2. SOURCE:

Natural dyes can be obtained from plants, insects or from mineral sources. The

Vegetable dyes can be obtained from the plants, the Animal dyes from insects and the Mineral

dyes from mineral sources. The vegetable dyes are available in nature in the form of plant bark,

root, flowers, leaves, fruit-cover etc. As many as 500 plant species are identified as useful

sources of dyes. For e.g. Turmeric, Canna, Mehendi, Indigo, Saffron, etc. are of plant origin.

However, it is unbelievable that the list of dye producing sources of animal origin is very small,

although a large variety of insects and other fauna are available, Secretions of insects like

cochineal, kermes and Lacca (Lac) are most commonly used. Some other sources of animal

dyes include higher animals for e.g. the yellow dye extracted from the urine of cow and probably

secretions of shellfish and molluscs (under investigation). Mineral dyes are not utilised at present

and their use has been discontinued as because many mineral colourants have been found to be

poisonous. The two most commonly referred to and used minerals are "Geru" and "Khaki". This

class of colourants is applied by impregnating the fabric with soluble metal salts, just like

mordanting process, followed by reaction to produce insoluble salts or hydroxides in-situ.

Indigo is the oldest dyestuff and has been known and employed for dyeing in India for

about 4000 years. The dye occurs as the colourless, crystalline glucoside. Indican, in the leaves

and branches of the Indigo plant, Indigofera tinctoria. Indigo is originally known as ‘nila’ and the

name indigo derived from the word indicum, the Indian substance. In the 13 th century Marco Polo

mentioned its cultivation in India. Portugeese imported Indigo from India and called it ‘anil’. The

yield of indigo is about 0.2% on the green plant. In 1880, India had 17 lakh acres of land for

indigo cultivation and 2800 factories wherein were employed 3.6 lakh workers. In 1896-97, India

produced 8,400 tons of Indigo and it reduced to only 510 tons in 1934 – 35. Based on the famous

German chemist, Adolf Von Bayer’s research, German (Badische, Anilin und Soda Fabrik or

BASF) started commercial production of synthetic indigo and as a consequence, in India, the

mother of Indigo, its cultivation had to be discontinued.

Madder or Alizarin is another important ancient natural dye. This dye occurs as a

glucoside in the root of madder (munjistha) and forms chief colouring matter of madder. This

plant was extensively cultivated and so its root has been used from the earliest times in India and

Egypt for dyeing Turkey Red.

Lac is the most ancient of the animal dyes. It has been used in India and Southeast Asia

since beginning of the recorded history. History of lac goes back to the Vedic period when it was

known as Laksha. Atharva Veda gives a brief account of lac, insect and its medicinal uses. The

Vinaya text of Buddhism describes the extraction method of lac dye and it's application to dyeing.

Ladies had known the great antiquity of lac dye for its age-old uses in dyeing silken sarees, alta

in religious ceremony for colouring of feet and palm of hands4. The word Lac or lakh was

originally associated with very large number of Lac insects (Indian Lac). The term was further

used as lake, i.e., for the insoluble salt of the dye i.e., pigments. The pigment derived from the

insect have no affinity for the fibre. Lake is formed by the action of the mordant and the dye.

Basically it is a mordanted dye on cellulose. India is the largest lac producing country and it is

largely found in Bihar, Madhya Pradesh, Orissa, West Bengal and to a lesser extent Assam,

Uttar Pradesh, Punjab, Karnatak and Tamil Nadu. Lac dye is basically a waste product and the

dye can be recovered in a simple process. Nearly 200 tons of recoverable lac dye is lost every

year, which can otherwise be utilised for textile industry 4,5.

3. UTILISATION :

Natural Dyes can be classified into two groups. These are (a) Substantive dyes and (b)

Adjective/Mordant Dyes. The First group is known as substantive or non-mordant dyes, which

produce a fast colour on textile materials directly by boiling. Indigo, Orchil, Turmeric etc. belong

to this class of dyes. The second group, which needs an additional chemical, the so-called

mordant, to make the colour permanent is termed as adjective or mordant dyes. In pure state

these dyes are generally only slightly coloured and when used alone give poor dyeing. Examples

of such dyes are logwood, madder, cochineal, fustic etc. In the olden day’s urine, saliva, egg

albumin, tannins and metallic salts were widely used as mordant. The same dye produced

different colours with different mordant. Due to the chelate formation between the dye molecules

and metal salts, the colours produced are reasonably fast and so, now-a-days metal salts are

mostly used as mordant.

The knowledge and use of color on textiles is one of the most important processes of

fabric development and utilization. Till 1856, when synthetic dyes were introduced, only natural

dyes were used. The invention of synthetic dyes have replaced natural dyes and nearly stopped

the use of natural dyes and colouring matters 6. In recent years, concern for the environment has

created a deep interest in natural dyes. This is further enhances with the analysis that some of

the synthetic dyes consist of harmful amines and chemicals. This created toxicological effects

and harmful effects on skin during wearing. So developed countries like German ban their uses.

European industry is more planned and oriented to use safe dyestuffs. Also, the production of

synthetic dyes involves many violent reactions with more by-products and / or pollutants for the

environments 7. As a result of this, natural dyes are recovering their lost importance. This is

because natural dyes are (a) fairly non-polluting, (b) Automatically harmonizing colours, and (c)

rare colour ideas. On the other hand natural dyes have the following drawbacks 8:

1. Only a few dyes have good fastness to washing and light

2. Shade reproducibility is difficult due to difference in maturity, climatic conditions etc.

3. Higher cost and limited range

4. Collection of the plant materials and insect secretions is a localised and cumbersome

operation

5. Transportation and distribution of raw bulk is major hindrance

6. A few mordents may harm the textile product for e.g., Traces of iron may tender silk 8

4. FUTURE ASPECTS:

Inspite of all these shortcomings, there is a demand on natural dyes because of the following

reasons:

(1) Replacement of synthetic dyes by natural dyes for eco friendly textiles

(2) Use of natural dyes in home craft work

(3) Restoration of old textiles for their aesthetic use

(4) Reconstruction of ancient and traditional dyeing technology

Owing to this, it is essential that there should be intense work on natural dyes as well as

on their dyeing behaviour and fastness properties, which will be helpful for their best practical

application. The present series will highlight the work related to dyeing behaviour and the

fastness properties of some selected natural dyes.

5. REFERENCES

1. B. C. Mohanty, et. al. ‘Natural dyeing process in India’, Calico Museum of Textiles, Ahmedabad (1987)2. Dr. M. L. Gulrajni, ‘Natural dyes and their application to Textiles’, edited by M. L. Gulrajni & Deepti

Gupta, IIT, New Delhi, 1992.3. Color Index, Society of Dyers & Colourist, 19714. S. C. Agrawalla, Ind. Text. J., 107, 10, 26 (1997) 5. S. K. Patra, Ind. Text. J. 108, 12, 40 (1998)6. I. Holme, Textile Dyer & Printer, Feb 11, 1987.7. S. Roy & S. Wagner, Am. Dyestuff Reporter, 80 (9), 32 1991.8. K. Ramasamy ‘Dyeing behaviour of Natural Dye’, M. Sc. Thesis, Alagappa University, Karaikudi, 1995