Page 12 - Basic Principles of Textile Coloration

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CHAPTER 1

An introduction to textiles, dyes and
dyeing

The manufacture of textiles is a major global industry. It provides vast quantities
of materials for clothing and furnishings, and for a variety of other end-uses. This
book deals specifically with textile coloration. It begins by introducing this subject
along with some technical terms and concepts related to dyes, fibres and dyeing.
At this stage, mastery of all the new ideas is not necessary. They will be
encountered again throughout the book.

Several examples of the molecular structures of dyes will be presented in this
chapter so that the reader gains some familiarity with the variations in molecular
size, shape and ionic character. Do not be intimidated by these. In due course, the
relationship between the key features of the molecular structure of a dye and its
dyeing properties will be more evident.

1.1 HISTORICAL BACKGROUND

1.1.1 Natural dyes and fibres

The production of fabrics and their coloration precedes recorded history. Several
cultures had established dyeing technologies before 3000 BC. These ancient
artisans transformed the available natural fibres – linen, cotton, wool and silk –
into fabrics, at first by hand, and later using simple mechanical devices. Short
fibres were first carded or combed, to lay them parallel to one another. Drawing
out of a band of combed fibres by pulling, with gradual twisting, produced yarn.
Finally, yarns were interlaced to form a woven fabric. The techniques used hardly
changed until the Industrial Revolution, when they became fully mechanised.

Although finely ground, coloured minerals, dispersed in water, were used in
paints over 30 000 years ago, they easily washed off any material coloured with
them. Natural dyes were extracted from plant and animal sources with water,
sometimes under conditions involving fermentation. Fabric was dyed by soaking it
in the aqueous extract and drying. These dyes had only a limited range of dull
colours and the dyeings invariably had poor fastness to washing and sunlight. The
fastness of a dyeing is a measure of its resistance to fading, or colour change, on

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