Question

In ________ a reducing agent is used to destroy the colour in printed portion.

• A. Resist printing
• B. Discharge printing
• C. Roller printing
• D. Automatic screen printing

Hint:

A reducing agent that removes the dye from the printed area is the mark of one printing style. Think of dyed cloth with a white design.

Answer 1

The Correct Option is B

Step 1: Understand the concept:
In some printing styles, the printer does not add colour to white cloth. Instead the printer works on cloth that is already dyed.
The question asks which style uses a reducing agent to destroy the ground colour only in the printed portion.

Step 2: Recall how discharge printing works:
The fabric is first dyed in a solid colour.
A printing paste with a reducing agent (for example sodium formaldehyde sulphoxylate) is then printed in the design.
The reducing agent breaks down the dye in the printed area, so that area turns white or light.
If a stable dye is added to the paste, that area takes a new colour.

Step 3: Check option (A) Resist printing:
Here a resist paste (wax, clay or chemical) is applied before dyeing. It blocks the dye from entering. No dye is destroyed, so (A) is wrong.

Step 4: Check options (C) and (D):
Roller printing and automatic screen printing are machine methods that name the equipment. They are not defined by a reducing agent, so (C) and (D) are wrong.

Final Answer:
A reducing agent that removes colour from the printed portion is used in discharge printing, which is option (B).