Question

................ is used to test the wash fastness of dyes in textile materials.

• A. Crock meter
• B. Xenon Arc lamp
• C. Launderometer
• D. Spirometer

Hint:

Always link: Launderometer → Wash fastness, Crock meter → Rubbing fastness, Xenon Arc → Light fastness.

Answer 1

The Correct Option is C

Step 1: Understanding wash fastness.
Wash fastness is the ability of a dyed fabric to retain its color when subjected to repeated washing with detergents and soaps. A fabric with high wash fastness does not bleed or fade easily during laundering.
Step 2: Instruments for different fastness tests.
- Crock meter is used to test rubbing fastness (how color resists rubbing).
- Xenon Arc lamp is used to test light fastness (resistance against sunlight/artificial light).
- Launderometer is used for wash fastness, as it simulates washing conditions (detergent, temperature, agitation).
- Spirometer is a medical device used for lung capacity measurement, unrelated to textiles.
Step 3: Why Launderometer?
The Launderometer subjects fabric samples to controlled washing cycles in solutions of soap/detergent at specified temperature and time. The change in color and staining is then assessed using grey scales.
Step 4: Conclusion.
Hence, Launderometer is the correct instrument used to test wash fastness of dyes.