Dyeing And Bleaching Paper 2 May/June 2015

Question 1

(a)      State one function of each of the following dyeing materials:
(i)       hydrosulphite;
(ii)       caustic soda;
(iii)       hand gloves;
(iv)       candle wax.


(b)        List any four processes of preparing a starch paste for batik.
(c)        List three tools for batiking.


Candidates’ performance in this question was quite impressive. Some candidates’ interchanged the functions of hydrosulphite for caustic soda and vice versa. Most of the candidates’ didn’t understand the processes of preparing a starch paste for batiking. They misinterpreted it for the processes of preparing wax/starch for batik production in the (b) part. Also, candidates’ are yet to understand the difference between materials and tools as was required in the (c) part, where they listed materials in place of tools. They were expected to respond to the question thus:
 (a)       (i)         Hydrosulphite:                       
-           It is a chemical that is used to retain/fix dye on fabric.
-           It is a chemical that improves the surface appearance of a dyed fabric.
-           It is a chemical that makes dye soluble in water.
-           It is a reducing agent in dyeing process.

           (ii)        Caustic Soda:             
-           It is used to open up fabric for the absorption of dye.
-           It is a principal/major chemical that fixes the dye and hydrosulphite in fabric during dyeing.

           (iii)       Hand gloves:              
-           To protect the dyers’ hands from contact with chemical solutions.
-           Used for turning fabric during dyeing.
-           Used to remove fabric from dye solution.

Candle wax:               

-           Used as a resist material in batik production.
-           Used to create patterns/designs on fabric.
-           Makes the fabric lustrous/shining.
-           Stiffens the fabric.

(b)        -           Source for starch.
-           Mix starch with cold water until the particles are broken/dissolved.
-           Boil water, pour into the starch solution and stir.
-           Allow the solution to cool to form a paste.
-           Paste is ready for use.

(c)        Tjanting, Knife, Blade, Boiling ring/Water heater, Scissors, Electric/Cold Pressing iron, Stove, Spoon, Bucket/Bowl, Industrial/Safety/Rain boot, Hand/Rubber gloves, Apron/Overall, Nose mask/guard, Mouth mask/guard, Padded table/Table, Safety glasses/Sun shade, Kettle, Jug, etc.