Observation

  Most candidates were unable to exhibit a thorough knowledge of bleaching agents involved in bleaching process instead they were mentioning the trade names of the finished products like Jik, Hypo which are not acceptable. What is requested of them to list are: sodium hydrosulphite; caustic soda; chlorine; hydrogen peroxide etc. Candidates failed to orderly outline the processes of achieving desings on a plain coloured fabric through bleaching using stencilling technique. Some misinterpreted the question by outlining the dyeing processes instead of bleaching processes. The candidates’ are yet to understand the content of this topic. They were expected to respond to the question in the following manner:

(a) It is a process of whitening/ removing the natural colour of textile, fibres/yarns and fabrics to form/create patterns/ designs by the treatment/ application of chemicals/bleaching agents.

 

(b) • Sodium hypochlorite;

• Hydrogen peroxide;

• Sodium chlorite;

• Fluorescent whitening;

• Sodium hydrosulphite;

• Caustic soda/Sodium hydroxide;

• Calcium hypochlorite;

• Chlorine;

• Thinner;

• Turpentine;

• Chlorine dioxide;

• Sulfurous acid;

• Sulphur dioxide;

• Sodium sulfoxylate formaldehyde;

• Sodium borohydride;

• Bisulfites;

• Sulfites.

 

(c) - Get all materials ready such as coloured fabric, stencil, bleaching agents/chemicals, nylon, bowl, brush, etc.

- Prepare a desired design on paper.

- Cut into stencil.

- Place the stencil on the plain coloured fabric.

- Apply the bleaching solution through the stencil to achieve patterns/designs on the fabric.

- Leave the bleaching solution to remain on the fabric for a while.

- Remove the stencil from the fabric.

- Rinse the fabric properly with water.

- Wash with soap and rinse again.

- Starch and dry the fabric.

- Iron the fabric.

- Package the fabric.