Color Fastness Test to Light | Light Fastness Grades

The purpose of Color fastness to light test is to determine how much the color will fade when exposed to a known light source. It is an off line quality assurance system. Generally man wears the fabric and goes outside of the home for doing their job. In day; sun light fall on the fabric surface. So it needs to know how much protection ability have a fabric to sun light. It is determined by an experiment called color fastness to light. To measure the color fastness a blue scale is used. After completing the test, sample is compared with the blue scale.
Light fastness tester
Fig: Light fastness tester
Principle of Color Fastness to Light:
This test measures the resistance to fading of dyed textile when exposed to day light. The test sample is exposed to light for a certain time which is about 24 hours to 72 hours or by customer/buyer demand and compare the change with original unexposed sample the changes are assessed by Blue Scales.

Light Fastness Grades:
Degree of Fading
Light Fastness Type
No fading
Very slight fading
Slight fading
Very good
Moderate fading
Appreciable fading
Significant fading
Extensive fading
Very extensive fading
Very poor

Color Fastness to Light with the Microsol light Fastness Tester:
The testing is done step by step. Following step is maintained during measure the color fatness to light.
  • Cut the four pieces of test specimens according to the length & width wise and attached with the specimen holder.
  • Then the holder set in to the Microsol light fastness tester.
  • Then the experiment continued at 72 hours according to the buyer’s requirement.
  • After 72 hours later the specimen taken from the light fastness tester
  • Then the test specimen compare with the Blue scale or computer color matching system (CCMS).
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Founder and Editor:

Mazharul Islam Kiron is a textile consultant, entrepreneur, blogger and researcher on online business promotion. He is working as a consultant in several local and international companies. He is also a contributor of Wikipedia.

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