How to Test the Color Fastness of Textiles?

The color fastness in textile is one of the most important tests that must be performed on the products to ensure that the color of the products is fast enough that the textiles could withstand the various processes such as rubbing, washing, light exposure and other factors during usage. Color fastness is basically the resistance of fabric against the fading or bleeding of its color.  These are the conditions, to which the textiles are normally exposed during general use. There are different types of color fastness that are conducted on the textile products.

Standards for Color FastnessThere are several standards used for governing these tests on textiles such as AATC (American Association of Textile Chemists and Colorists) which has a complete manual that describes different tests for color fastness. In addition that, there are SDC (Society of dyers and color fastness) and ISO (International Organization for Standardization) standards that are used for conducting color fastness tests in textiles. These standards provide basic requirements that are essential for accurate color fastness test on textiles.

ISO 105-F09:2009 Textiles — Tests for colour fastness — Part F09: Specification for cotton rubbing cloth 

Factors Affecting Colorfastness in Textiles

1. The chemical nature of the fiber has a major effect on the color fastness. For Example, if a cellulose fiber is dyed with a vat or reactive dye then it will exhibit very good fastness of color.
2. The molecular structure of the dye also affects the color fastness. Dye with a larger molecule will show better fastness as it will be tightly trapped in the polymeric chain of the fiber.
3. The process of dyeing and the way in which the process of bonding takes place.
4. The depth of the shade also tends to affect the color fastness of textiles. Deeper shades show less fastness as compared to pale or lighter shades.
5. The other chemicals that are used during the process of dyeing also affect the color fastness process.

Colorfastness test

The color fastness test is performed in different ways for different types of analysis such as color fastness to light, to rubbing, and color fastness to washing, etc. The color of the sample is measured using proper textile color measurement instruments. Then the sample is subjected to test conditions. After the test is completed, the color of the sample is measured again. This gives the difference in the color intensity, and hence, the color fastness is evaluated.

In order to measure the color of the sample before and after the test, appropriate textile color measurement instruments should be used. The portable spectrophotometers offered by Testronix is one of the best testing instrument that allows the users in the precise evaluation of the textile samples with proper calculation of color difference and color space formulas.