Light Fastness Test of Fabric

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Light Fastness Test:

Color fastness is a term used in the dyeing of textile materials, meaning resistance of the material’s color to fading or running. The term is usually used in the context of clothes. Light fastness is the degree to which a dye resists fading due to light exposure. Different dyes have different degrees of resistance to fading by light. All dyes have some susceptibility to light damage. The light fastness of textile dye is categorized from one to eight and the wash fastness from one to five. The higher the number the better fastness is obtained.


Purpose of Light Fastness Test:

Light fastness is the test design to evaluate the laundering fastness test of dyeing, Pigment which re to be made in comparison of result obtained on many test pieces treated under light.


Method: ISO


  1. Light  fastness tester & blue scale
  2. scale
  3. scissor
  4. hard paper (11cm X 4.5 cm)


Working Procedure:

At first, we took the blue woolen cloth & test sample. The blue woolen clothes were dyed with acid blue, 104,109 etc. Then we cut the woolen cloth & sample according to template. The blue woolen cloth is cut to make standard & sample is cut to test light fastness. Then we put the holder of woolen cloth and sample in the set of machine and set the time, which was 24 hrs. After completing the process we get the slandered test result. Then we compared with the standard rating.


Light Fastness Grades:

Grade Degree of Fading Light Fastness Type
8 No fading Outstanding
7 Very slight fading Excellent
6 Slight fading Very good
5 Moderate fading Good
4 Appreciable fading Moderate
3 Significant fading Fair
2 Extensive fading Poor
1 Very extensive fading Very poor




The test result of light fastness test is equivalent to the class of standard. If grade is 6. So we can say that the color fastness of dyed fabric is very good.


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