waecE-LEARNING
Dyeing & Bleaching Paper 2, May/June 2014  
Questions: 1 2 3 4   Main
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Question 1

QUESTION 1

  • What is a dye?
  • List four types of common dyes.
  • Explain the processes of dyeing a fabric with two colours using tieing method.

Candidates’ performance in this part was impressive. Although, some candidates could not differentiate between dye (a chemical) and dyeing (the process). Some candidates who were unable to do this lost enormous marks.They were expected to respond to the question thus:

  • It is a colouring substance that changes the colour of a fibre, fabric or other

textile materials to a relatively permanent state.
Or
            It is a chemical compound which impart colours to other textile materials by
            saturating them in a liquid solution.
Or
            It is a substance made from plants or chemicals which is mixed into a
            solution and used to change the colour of fabric, fibre or yarn.

  • Types of dye are:
  • Azonic                         (ix)       Sulphur                        (xvii)    Pigment
  • Vat                              (x)        Chrome/Metallic         (xviii)   Indigo
  • Basic                           (xi)       Developed                   (xix)     Acetate
  • Direct                          (xii)      Indanthrene                 (xx)      Alizarin
  • Reactive/Procion         (xiii)     Indigosol                     (xxi)     Aniline
  • Synthetic                     (xiv)     Dylon                          (xxii)    Aridyes
  • Natural                                    (xv)      Disperse
  • Acid                            (xvi)     Mordant
  • -      Get all materials ready such as the fabric, dyes, chemicals, tieing rope, bowl,

                              rubber gloves and hot water for dissolving the chemicals.

  • Plan the design on the fabric and resist some areas by tieing the first colour.
  • Dip the fabric inside the first colour solution (which should be the lighter

colour) and leave to absorb.

  • Resist the fabric for the second colour by tieing again some areas of the fabric.
  • Prepare the second dye solution, dip the fabric in it and leave to absorb.
  • Remove the fabric from dye solution and spread to oxidize.
  • Loose the tied areas and rinse to remove excess dye on the surface of the fabric.
  • Dry the fabric.
  • Iron the fabric and package.
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