Garment Fabric Colorfastness Testing

Garment fabric colour fastness testing mainly conducts scientific testing and analysis on colour fastness to washing with soap or soap and soda, colour fastness to rubbing, colour fastness to perspiration, colour fastness to light, colour fastness to water, and colour fastness to the composite action of saliva and perspiration, objectively assessing the product quality grade and issuing a detailed test report, providing a basis for manufacturers' quality control and downstream users' product acceptance.

Testing Items

Colour fastness to washing with soap or soap and soda: Evaluates the ability of the textile to resist fading of its own colour during household or commercial washing, as well as the degree of staining that may be caused to other fabrics washed together. This test mainly simulates daily washing conditions and is one of the key indicators for measuring the durability of garment fabrics. The result directly affects the wearing experience of consumers and the evaluation of the product.

Colour fastness to rubbing: Tests the tendency of the colour of the textile to transfer to the surface of other fabrics under dry or wet rubbing. It is divided into dry rubbing and wet rubbing tests, with the wet rubbing test being more stringent. This item is crucial for garment fabrics at parts that are frequently contacted and rubbed (such as cuffs and collars), and is an important link in controlling the appearance quality of the product.

Colour fastness to perspiration: Determines the ability of the textile to retain its colour under the action of simulated human perspiration. Perspiration is usually a mixture of acidic and alkaline substances, which can damage or dissolve the dye, causing the colour to come off or transfer to the skin or other clothing. This test is directly related to the wearing safety and comfort of garments.

Colour fastness to light: Evaluates the ability of the textile to resist fading or discoloration of its colour under irradiation of sunlight or artificial light sources (such as xenon arc lamps). Especially for products such as outdoor clothing, curtains and automotive interiors that are exposed to sunlight for a long time, light fastness is the core performance indicator for measuring their service life and appearance retention.

Colour fastness to water: Tests the shedding of the colour of the textile itself and the degree of staining on the adjacent fabric in contact when immersed in water. This test simulates the colour stability of garments under conditions such as rain, washing or wetting by perspiration, and is especially important for fabrics such as swimwear and sportswear.

Colour fastness to the composite action of saliva and perspiration: This is a mandatory safety test item for infant and children's textile products (especially Class A products). It mainly evaluates whether the colour of the fabric (especially dark or bright colours) is easy to come off under the joint action of saliva and perspiration, to prevent harmful substances in the dye from being sucked or swallowed by infants and children. It is a key test for ensuring the health and safety of children.

Colour fastness to chlorinated water (swimming pool water): Specifically tests the colour stability of fabrics such as swimwear and bath towels in water containing chlorine disinfectants (such as swimming pool water). Chlorine-containing substances such as hypochlorite have strong oxidizing properties and easily cause some dyes to decompose and fade, so special test methods and standards are needed for evaluation.

Testing Scope

Fabrics of various fibre compositions: The testing scope covers natural fibres such as cotton, linen, silk and wool, as well as chemical fibres such as polyester, nylon, acrylic and viscose, and their blended and interwoven fabrics. Different fibres have different dyeing mechanisms and dye types, and their colour fastness performances vary, so targeted testing is needed.

Products of different dyeing and printing processes: Including dyed fabrics (such as direct dyeing, reactive dyeing and vat dyeing), yarn-dyed fabrics and printed fabrics. Especially for printed fabrics, the various colour fastness of the ground colour and the print need to be evaluated separately, because the printing paste and fixation process directly affect the adhesion fastness of the colour.

Finished garments and semi-finished fabrics: The test objects can be either finished garments (such as shirts, trousers and coats) or uncut grey fabrics or fabric rolls. Finished product testing can better reflect the actual performance after wearing, while fabric testing helps to carry out quality control before production.

Fabrics with special finishing: For fabrics that have undergone special finishing processes such as waterproofing, stain resistance, flame retardancy, UV resistance, enzyme washing, stone washing and brushing, the finishing agents may react with the dye or change the fibre surface structure, thus affecting the colour fastness, so special evaluation is needed.

Infant and children's textile products: In accordance with the mandatory standard GB 31701 "Safety technical code for infants and children textile products", there are clear and stricter assessment requirements for items such as colour fastness to saliva of Class A products (infant textile products), which is the focus of market supervision.

Home textiles: Home textile products such as bed sheets, quilt covers, curtains and sofa covers also need colour fastness testing, especially light fastness, washing fastness and rubbing fastness, to ensure that they maintain a good appearance during daily use and cleaning.

Industrial textiles: Some industrial textiles, such as automotive interior fabrics and outdoor tent fabrics, have extremely high requirements for light fastness, weather fastness and rubbing fastness due to their special service environment, and the testing standards and methods are also more professional.

Testing Methods

Standard adjacent fabric method: This is the most classic and general test method. The sample to be tested is sewn together with a standard multifibre adjacent fabric or single-fibre adjacent fabric, and treated in a specific test solution (such as soap solution, perspiration or water). The colour change (fading) of the sample and the degree of staining of the adjacent fabric before and after treatment are rated using standard grey scales.

Rubbing fastness tester method: A dedicated rubbing fastness tester is used. The sample of specified size is fixed on the platform, and a rubbing finger wrapped with standard white cotton cloth carries out a specified number of reciprocating rubs on the sample surface. After carrying out dry and wet tests respectively, the grade is determined by evaluating the staining on the white cloth.

Light fastness tester method (xenon arc lamp): The sample is placed in a xenon arc lamp test chamber together with a set of blue wool reference standards, and exposed under specified temperature, humidity and light conditions. The light fastness grade is determined by comparing the fading degree of the sample with that of the blue wool reference standards. This method can simulate natural sunlight well.

Perspiration fastness tester method: The composite specimen (fabric sandwiched between adjacent fabrics) is immersed in artificially prepared acidic or alkaline perspiration solution to make it completely wet. Then, in a perspiration fastness tester (or constant temperature oven), it is kept for a certain time under specified temperature and pressure, simulating the state of long-term contact between the perspiration and the fabric, and finally dried and rated.

Soaping fastness testing machine method: The composite specimen is placed in a stainless steel container, soap solution of specified concentration and steel balls are added, and after sealing, it is placed in a soaping fastness testing machine. The machine rotates at a specific speed at a constant temperature, simulating the mechanical agitation in the washing process. After treatment, the specimen is washed and dried, and then rated.

Rating methods (grey scales and instrumental rating): Mainly the internationally used grey scales for visual rating. This includes the "grey scale for assessing change in colour" (used to rate the colour change of the sample itself, grades 1-5, with 5 being the best) and the "grey scale for assessing staining" (used to rate the degree of staining of the adjacent fabric, grades 1-5, with 5 being the best). In recent years, colorimeters (color difference meters) have also been increasingly used to objectively and quantitatively rate the colour difference, to reduce human error.

Saliva fastness test method: This is a special test for infant products. Artificial saliva (simulating the saliva composition of infants) is used to wet a white adjacent fabric, which is then placed in contact with the sample to be tested and kept for a period of time under conditions simulating the infant body temperature (37 ℃). Finally, the staining of the adjacent fabric is evaluated.

Testing Standards

Domestic Standards:

1. GB 18401-2010, National general safety technical code for textile products

2. GB/T 3920-2024, Textiles — Tests for colour fastness — Colour fastness to rubbing

3. GB/T 3921-2008, Textiles — Tests for colour fastness — Colour fastness to washing with soap or soap and soda

4. GB/T 3922-2013, Textiles — Tests for colour fastness — Colour fastness to perspiration

International Standards:

1. ISO 105, Textiles — Tests for colour fastness

2. ISO 13934-1, Textiles — Tensile properties of fabrics — Part 1: Determination of maximum force and elongation at maximum force using the strip method

Note: The applicable standard can be selected according to the product use and customer trade requirements; standards agreed in the contract take precedence over general standards.

Testing Instruments and Equipment

Washing fastness testing machine: This equipment is the core instrument for testing colour fastness to washing and dry cleaning. It is usually equipped with multiple sealable stainless steel sample containers, can maintain a precise temperature in a constant temperature water bath, and generates mechanical agitation through rotation, simulating the real washing process. Common models need to comply with the requirements of standards such as ISO, AATCC and GB.

Rubbing fastness tester: A relatively simple reciprocating mechanical device, composed of a base, a sample holder, a reciprocating rubbing arm and a rubbing finger. The key component is the rubbing finger and the standard cotton cloth wrapped around it. The equipment can precisely control the stroke, pressure and number of reciprocations of the rubbing finger, ensuring the repeatability and comparability of the test results.

Xenon arc lamp weather resistance test chamber: High-end equipment for light fastness and weather fastness testing. Its core is a xenon arc lamp that can emit spectral energy distribution close to sunlight. The chamber can precisely control the light intensity, black panel temperature, air humidity in the chamber and spray cycle, to simulate various outdoor light and damp environments.

Perspiration fastness tester (constant temperature oven): This equipment is essentially an oven or dedicated tester that can provide constant temperature and pressure. Its function is to place the perspiration-soaked composite specimen between two plates under specified pressure, and keep it for a specified time under a constant temperature (usually 37 ℃), so that the perspiration and the dye fully interact.

Standard light source color assessment cabinet: Crucial in the colour fastness rating link. It provides multiple standard light sources such as D65 daylight, TL84 store light, CWF cool white fluorescent light and UV light, ensuring that the rating personnel observe the colour change and staining of the sample under uniform, stable light source conditions free of ambient light interference, and guaranteeing the objectivity and fairness of the rating results.

Rating auxiliary tools (grey scales and white cloth for staining): Including the grey scales for assessing change in colour and staining in accordance with the provisions of ISO 105-A02 and A03, as well as standard multifibre adjacent fabrics DW (containing six fibres) or single-fibre adjacent fabrics (such as cotton, wool and nylon). The standardization of these consumables is the basis for ensuring the comparability of test results worldwide.

Colorimeter (colour difference meter): A precision electronic instrument used for auxiliary rating in modern laboratories. It calculates objective data such as the L*a*b* values and the ΔE colour difference value by measuring the surface reflectance spectrum of the sample before and after the test, providing a quantitative basis for determining the colour fastness grade, especially suitable for arbitration or occasions requiring extremely high precision.