Fundamentals of Textile Design 3(2+1)

Lesson 24: Dyes and Dyeing

Terminology

• Dye is a small particle of an organic compound composed of a chromophore, and an auxochrome. Chromophore is the color producing portion of the dye molecule while auxochrome alters intensity or brilliance of the colour. It also helps the dye in its solubility in water.


• Pigments are insoluble colour particles that are held on the surface of fabric by binding agents mechanically.


• Fluorescent dye glows under ultraviolet light. It absorbs light at one wave length and emits that energy at another wavelength. Fluorescent dyes are used in safety clothing to increase visibility of the wearer at night.
  


• Dye process is the environment created for the introduction of dye by hot water, steam, or dry heat.
  


• Colour flare or metamerism: When two or more types of fabrics are dyed, particularly by different dyers, the colours may appear to match in one light (day light) but will not match in another light (incandescent light).
  


• Mordant - a chemical that aids in the attachment of a dyestuff to fibres by bonding to both the fibre and the dye.
  


• Optical brightener - a fluorescent dye used to make white textiles appear brighter; also called fluorescent brighteners or fluorescent brightening agents (FBA).


• Union dye - a dye that is a mixture of two or more different classes of dye, used typically to dye blends of fibres.
  


• Level dyeing is uniform in shade over the surface of a piece of dyed fabric or along the length of dyed yarn.
  


• Fixation - formation of the “final” bond between the dye and fibre.
  


• Crocking - transfer of color from dyed or pigmented fabric by rubbing.
  


• Affinity - attraction between two items; in dyeing affinity essentially means the preferential attraction of the dye for the fibre rather than for the solution of the dye bath.


• Bleeding is colour loss in water.


• Migration is shifting of colour to the surrounding area or to an adjacent surface