Color fastness to washing is one of the most critical quality indicators for apparel fabrics, measuring how well dyed and printed textiles retain their color and avoid staining adjacent materials during domestic and commercial laundering. This technical article explains the test samples, evaluation items, standardized methods such as ISO 105-C06, AATCC 61 and GB/T 3921, typical applications, and answers frequently asked questions about wash fastness testing.
Technical Overview
Color fastness to washing refers to the ability of a dyed or printed textile to resist color change and color transfer when subjected to laundering processes that simulate domestic and commercial washing conditions. Poor wash fastness causes fading, dulling of shades, and staining of other garments in the same wash load, which is one of the most common sources of consumer complaints and product returns in the apparel industry.
Wash fastness testing is performed by preparing a composite specimen that combines the fabric under test with a standard adjacent or multifibre fabric, exposing it to a controlled washing solution in a rotating mechanical washing device, and then evaluating two aspects: the change in color of the specimen itself and the degree of staining transferred to the adjacent fabric. Results are expressed on a grey scale rating from 1 (very poor) to 5 (negligible or no effect), with half-step ratings such as 4–5 permitted.
The most widely applied standards for this test include:
- ISO 105-C06 (Textiles — Tests for colour fastness — Colour fastness to domestic and commercial laundering), adopted in Europe as EN ISO 105-C06 and in China as GB/T 3921.
- AATCC 61 (Colorfastness to Laundering, Home and Commercial: Accelerated), the principal method used in North American supply chains.
- JIS L 0844, the Japanese method for colour fastness to washing.
- ISO 105-A02 and ISO 105-A03, which define the grey scales used for assessing change in color and staining respectively, together with the corresponding AATCC Evaluation Procedures.
Testing Samples
Woven and Knitted Apparel Fabrics
The core sample type is finished apparel fabric, including woven shirting, denim, suiting, jersey, interlock and other knitted constructions. Fabrics are tested in their final finished state, since dyeing auxiliaries, softeners and finishing agents can significantly influence washing performance.
Printed Fabrics
Printed textiles such as pigment prints, reactive prints and discharge prints are tested with the printed side placed in direct contact with the adjacent fabric so that staining onto light-colored areas and cross-staining between printed and ground colors can both be assessed.
Dyed Yarns, Sewing Threads and Trimmings
Yarns and threads are wound onto a suitable carrier or laid parallel to form a thin layer, then sandwiched between adjacent fabrics to form the composite specimen. This is essential for evaluating sewing thread that may bleed onto garment panels during laundering.
Coated, Laminated and Functional Fabrics
Water-repellent, coated, laminated and other functional fabrics are tested to verify that surface treatments do not degrade washing performance of the underlying coloration system and that coating components do not transfer onto adjacent materials.
Multifibre and Standard Adjacent Fabrics
Adjacent fabrics are the reference materials that receive the transferred dye during the test. Multifibre adjacent fabrics containing bands such as wool, acrylic, polyester, nylon, cotton and acetate (for example types DW and TV) allow staining on each fiber type to be evaluated simultaneously, providing a complete picture of cross-staining risk.
Testing Items
Typical test items offered by accredited third-party laboratories for wash fastness evaluation include:
- Color fastness to domestic laundering at 40 °C, 50 °C or 60 °C for everyday apparel products.
- Color fastness to commercial and heavy-duty laundering at elevated temperatures up to 95 °C for workwear and industrial textiles.
- Color fastness to laundering with sodium perborate or other oxidizing agents in the detergent system.
- Color fastness to washing with chlorine bleach, principally under the AATCC 61 Test 4A and 5A procedures.
- Assessment of change in color of the test specimen using the grey scale for color change.
- Assessment of staining on the multifibre or adjacent fabric using the grey scale for staining.
Testing Methods
Specimen Preparation
A specimen of the fabric under test, typically measuring 100 mm × 40 mm, is placed in face-to-face contact with a multifibre adjacent fabric of the same size and stitched along one short edge to form a composite specimen. Specimens are conditioned in a standard atmosphere before testing.
Equipment and Reagents
The principal apparatus is a mechanical washing device, commonly known as a launderometer or gyrowash, consisting of sealed stainless-steel containers rotated in a temperature-controlled water bath. Standard reference detergents such as ECE reference detergent for ISO methods and AATCC reference detergent without optical brighteners for AATCC methods are used, together with stainless-steel balls that provide mechanical abrasion and distilled or deionized water at a defined liquor ratio.
Test Conditions
Test severity is selected according to the intended end use and the care label of the product. Representative conditions include:
- Mild conditions at 40 °C for 30 to 45 minutes, simulating gentle laundering of delicate articles.
- Moderate conditions at 50 °C to 60 °C for 30 minutes, with steel balls added for durable articles.
- Severe conditions at 70 °C to 95 °C for 30 minutes with sodium perborate and a large number of steel balls, simulating industrial laundering of workwear.
- AATCC 61 accelerated tests, in which Test 2A at 49 °C for 45 minutes is designed to be equivalent to five home launderings, while Tests 3A, 4A and 5A apply higher temperatures and bleach to evaluate more aggressive washing.
Post-Treatment and Drying
After washing, the composite specimen is rinsed twice in cold water, once in flowing cold water, and drained. It is then separated from the adjacent fabric, except along one edge, and dried in air at a temperature not exceeding 60 °C.
Evaluation and Reporting
The change in color of the specimen and the staining of each band of the adjacent fabric are assessed against the grey scales by trained observers under a standardized D65 light source in a color assessment cabinet, or instrumentally using a spectrophotometer. Results are reported as grade 1 to 5, with higher grades indicating better fastness. The test report identifies the standard and severity condition used, the detergent, the adjacent fabric type, and the numerical grades for color change and staining on each fiber band.
Applications
Wash fastness testing is applied throughout the textile and apparel value chain for multiple purposes:
- Incoming fabric inspection and supplier quality control before bulk garment production.
- Compliance with buyer and retailer technical manuals, which commonly require minimum grade 4 for both color change and staining, with grade 3–4 accepted for selected products and dark shades.
- Verification of care label instructions, ensuring that declared washing temperatures will not cause unacceptable fading or staining.
- Support for market access in the European Union, North America and other regions, where compliance with EN ISO 105-C06, AATCC 61 or GB/T 3921 is routinely documented in test reports from accredited third-party laboratories.
- Research and development of dyes, auxiliaries and after-treatment processes, where wash fastness data guide the selection of dye classes, fixation agents and soaping procedures.
- Evaluation of workwear, uniforms and industrial textiles subjected to repeated commercial laundering throughout their service life.
FAQ
What grade is considered acceptable for color fastness to washing?
Most international buyers specify a minimum of grade 4 for both color change and staining on all adjacent fibers, particularly for garments that will be washed together with light-colored items. Some product categories, such as deep navy or black denim, may be accepted at grade 3–4 depending on the retailer specification and the declared care instructions.
What is the difference between ISO 105-C06 and AATCC 61?
ISO 105-C06 uses ECE reference detergent, a liquor ratio of 100:1 in most conditions, and a temperature ladder from 40 °C to 95 °C, and it is the reference method in Europe and China as GB/T 3921. AATCC 61 uses AATCC reference detergent, a 50:1 liquor ratio, and accelerated procedures such as Test 2A, in which a single 45-minute cycle is equivalent to five home launderings. The two methods are correlated but not directly interchangeable, so the method must always be agreed between buyer and supplier.
Can a single test replace multiple home washes?
Yes. Accelerated methods compress the mechanical, thermal and chemical action of several launderings into one controlled laboratory cycle, which is why they are used for routine quality control. However, they do not replace real-life assessment of effects such as seam puckering, shrinkage or surface appearance, which require repeated home laundering tests.
Why can a fabric show good color change but poor staining?
Color change and staining measure different failure modes. A fabric may retain its own shade well while releasing unfixed surface dye that transfers to adjacent fibers. This is common when soaping and washing-off after dyeing are insufficient, and it is precisely why both aspects must be graded separately.
How can wash fastness be improved?
Effective measures include selecting high-fixation dye classes appropriate to the fiber, optimizing dyeing temperature, time and pH, applying thorough washing-off and soaping with suitable auxiliaries, using cationic fixing agents where appropriate, and ensuring that finishing agents do not redeposit unfixed dye on the fabric surface.