What Is A Color Fastness Test And Why Does It Need To Be Done?

Color fastness generally refers to the strength of the textile fabric, footwear, leather against the influence of external factors. The ability of fabrics to hold its original color is undoubtedly the most vital property of textiles. As a result, color fastness is one of the crucial criteria of the buyer’s demand.

Fastness properties are generally expressed in ratings of fastness which normally ranges from rating 1~5.5 means unchanged while rating 1means major changes.

❖ What are Types of Color Fastness?

Requirements of color fastness of textiles vary with their respective use and process. For instance, less washable cloth requires low colorfastness, but it needs high lightfastness. Fabrics aiming for the summer season should have higher perspiration fastness, light fastness, and washing fastness

However, color fastness is diverse, and likely there are several types of color fastness such as

  • Color fastness to water
  • Color fastness to chlorinated water
  • Color fastness to washing
  • Color fastness to heat
  • Color fastness to friction
  • Color fastness to burning
  • Color fastness to cold
  • Color fastness to saliva
  • Color fastness to seawater
  • Color fastness to hypochlorite bleach

Different countries have set different standards for the different colorfastness requirements of different textiles.

❖    Factors Affecting the Color Fastness Properties

The following factors have substantial effects on color fastness properties of fabrics.

  1. The purity of fiber: Proper selection of cotton fiber is the prerequisite of getting good colorfastness. During the spinning of fiber, if there exists any immature fiber or dead fiber or even short fiber, then colorfastness be getting low.
  2. Nature of the fiber: The chemical characteristics of fiber are probably the most significant factor. For instance, cellulosic fibers that are dyed with reactive usually show good fastness properties. Similarly, protein fiber that is dyed with acid-mordant and reactive dyes also possesses fastness properties.
  3. Molecular structure of dye molecule: Fastness is normally better if the dye molecule is bigger in size.
  4. Types of dyes: The degree of color fastness of fabric certainly depends on the type of dyes being used in the dyeing process.
  5. Other Chemicals: The presence of other chemicals in the material also
  6. Environmental conditions: The ambient condition during the dyeing process also influences the color fastness of the fabric.

❖    How to Test Color Fastness?

fabric color fastness testerColor Fastness Test Methods in the Textile and Apparel Industry can be performed in numerous ways such as-

1. Low-Temperature Launder-Ometer:

 It is one of the common processes to examine color fastness to washing or rubbing by the accelerated method. A device is used to simulate industrial procedures. In this process, firstly, clothes have kept containers with detergents or cleaning agents.  Secondly, a metallic ball is usually used for friction to evaluate colorfastness quality.

Followings instruments are usually seen in textile industries.

  • Perspirometer; which is commonly used for checking the resistance capability of clothing colors against water as well as perspiration. Firstly, wet the cloths by mixing solutions akin to sweat. Secondly, apply pressure. Finally, assess the quality fabric.
  • Electronic Crock Meter; is useful because it tests colorfastness to both dry and wet rubbing. Electronic Crock Meter replaces the mechanical Crock Meter recently because of being more accurate and convenient.
  • Color Matching Cabinet: To inspect colorfastness visually, Color Matching Cabinet is preferable to many textile industries. Fabrics, which come up with nominal variance from the original one after the external effects, are considered good fabrics.

2. Weather-o-meter:

This machine is used to test color fastness of the fabric against sunlight and to arrange such ambient conditions, and artificial lights are being used. How long fabric can retain from being exposed as well as the level of exposure in terms of time usually determines the degree of color fastness of fabric.

Light Fastness Tester: It is used to check the color fastness against sunlight as well as the degradation of textiles and dyed material.

3. Launder-o-meter:

This device examines how clothes will look like after being washed.

Washing Fastness Tester: This device is used to check the quality of fabrics after washing.

4. Surface Abrader:

This machine determines color fastness of clothes against frosting.

Standards of color fastness:

The following organization sets the guideline for testing color fastness.

  • AATCC(American Association of Textile Chemists and Colorists)  technical manual:
  • SDC(Society of Dyers and Colorists):
  • ISO(International Organization for Standardization):
  • ASTM (American Society for Testing and Materials)

Gray Scale:

Greyscale is an experimental scale containing a series of pairs of neutrally colored chips that reflect the difference in contrast within pairs. Buyers can inspect different samples visually and compare with standard to come up with a decision.

There exist two types of greyscale –

  • Color change
  • Staining

Grade for Wash & Other fastnesses:

Fastness grade Shade change of tested sample Fastness quality Staining of adjacent white sample
5 No change Excellent No staining
4 A little loss in depth Good Very slight staining
3 Considerable loss Fair Moderate  staining
2 Significant loss Poor Significant staining
1 Huge loss in depth Very poor Deep staining

Grade for Lightfastness:

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

To conclude, Color Fastness is an important indicator to measure the quality of dyeing products. Colors are, however, expected to last longer than the initial few washes. Additionally, the criteria for color fastness differs based on the use of the textile. But, different countries set various standards for the different color fastness requirements of different textiles. If you plan to import fabric or yarn from China, you may get in touch with a reliable, trustworthy, and renowned third party that is equipped with subject matter experts and a world-class laboratory. AQI Servicecertainly would be your first choice.

Related:

Textiles and Garments Quality Inspection

Bedding and Home Textile Products Quality Inspection

Author: AQI Service as a professional quality control service company in China specialized in providing a complete range of quality inspection and testing certification services in China & Asia for global importers, buyers, retailers, and sellers.



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