What is color fastness? Why test for color fastness?

Color fastness refers to the degree of fading of dyed fabrics under the action of external factors (extrusion, friction, washing, rain, exposure, light, seawater immersion, saliva immersion, water stains, sweat stains, etc.) during use or processing.

It grades the fastness based on the discoloration of the sample and the staining of the undyed backing fabric. The color fastness of textiles is a routine test item in the intrinsic quality test of textiles. It is an important indicator of fabric assessment.

Good or bad color fastness directly affects the beauty of wearing and the health and safety of the human body. In the process of wearing a product with poor color fastness, it will cause the pigment on the fabric to fall off and fade when it encounters rain and sweat. Heavy metal ions, etc. may be absorbed by the human body through the skin and endanger the health of the human skin. On the other hand, it will also affect other clothing worn on the body from being stained.

Types of Color Fastness Testing:

The dye fastness of fabric is related to the type of fiber, yarn structure, fabric structure, printing and dyeing method, dye type and external force.

The test of color fastness generally includes color fastness to soaping, color fastness to rubbing, color fastness to perspiration, color fastness to water, color fastness to light (sun), color fastness to sea water, and color fastness to saliva. Fastness, color fastness to chlorine water, color fastness to dry cleaning, color fastness to heat pressure, etc. Sometimes there are some special requirements for color fastness according to different textiles or different environments.

Usually, when the color fastness test is carried out, it is the degree of discoloration of the dyed object and the degree of staining to the lining material. For the color fastness rating, except for the color fastness to light, which is grade 8, the rest are grade 5. The higher the grade, the better the color fastness.


The color fastness to soaping is to simulate the color change of the textile and the staining of other fabrics during the washing process of the washing liquid. The sample simulates washing by colliding with the container and stainless steel beads.

The color fastness to rubbing is the degree to which the color of a colored textile is simulated to transfer to another fabric surface due to rubbing. It can be divided into dry friction and wet friction.

Color fastness to perspiration is the fastness of simulated textiles to artificial perspiration.

Color fastness to water is the degree to which the color of a textile is simulated after being immersed in water.

Color fastness to light (sun) is the degree to which a textile is simulated to be discolored by sunlight.

Post time: Jun-10-2022