Cross-staining colour fastness testing evaluates whether dyes migrate from dark-coloured textile components onto lighter-coloured components in joined or assembled products such as colour-block garments, contrast trim panels, and patchwork home textiles. Conducted in accordance with standards such as GB/T 31107, ISO 105 series methods, and AATCC 163, this testing helps manufacturers prevent dye transfer defects, meet finished-product specifications, and avoid costly consumer complaints. This article explains the principle, sample requirements, test methods, evaluation criteria, and typical applications of cross-staining colour fastness testing.
Technical Overview
Cross-staining colour fastness refers to the resistance of a textile assembly to the transfer of dye from one coloured component to another when the joined components are exposed to moisture, perspiration, washing, or humid storage conditions. Unlike conventional staining fastness tests, in which colour transfer is assessed against a standard white adjacent fabric, cross-staining testing evaluates staining between the actual components of the product, for example a dark navy panel stitched to a white or light-grey panel in the same garment.
The failure mode is common in products that combine fabrics of different colours and dye classes: reactive dyes, sulphur dyes, indigo denim, and poorly fixed direct dyes can bleed during wet treatment and redeposit on adjacent lighter areas, producing visible discoloration along seams and panel boundaries. Because such defects typically appear only after the consumer launders or wears the product, laboratory simulation is essential for risk control before shipment.
- Primary method standard: GB/T 31107-2014, the Chinese national standard for colour fastness to cross staining of textiles.
- Supporting assessment standard: ISO 105-A03 / GB/T 250 grey scale for staining, used to grade the stained lighter component.
- Related treatments: ISO 105-E01 (water), ISO 105-E04 (perspiration), ISO 105-C06 (domestic and commercial laundering).
- Storage-related transfer: AATCC 163, covering dye transfer from fabric to fabric during storage.
Results are expressed on the grey scale for staining, where grade 5 indicates no visible staining and grade 1 indicates severe staining. Intermediate ratings such as 4-5, 4, and 3-4 are routinely reported. Many finished-garment specifications in international trade require a minimum of grade 4 for products containing sharply contrasting joined components.
Testing Samples
Colour-Block and Contrast-Panel Garments
The most frequently submitted samples are garments combining dark and light panels, such as sportswear with contrast side panels, school uniforms with contrasting collars and cuffs, and casual wear with colour-blocked bodices. Both the potentially bleeding component and the vulnerable lighter component must be included in the specimen set.
Sewn Seams and Trims
Additional sample types include rib bindings, knitted collars, woven tapes, lace edgings, zipper tapes, embroidered logos, and printed labels attached to lighter base fabrics. Any component that touches another colour in the finished product is a candidate for evaluation.
Home and Technical Textiles
Sample Preparation and Size
Laboratories typically cut paired strips of each joined colour, commonly on the order of 100 mm by 40 mm per component, and secure them together by stitching along one edge to reproduce the assembly geometry of the finished product. When the submitted item already contains the seam, the joined area is cut directly so that the original construction is preserved. Multiple component pairs are prepared so that each test liquid, such as water, acid perspiration, and alkaline perspiration, can be evaluated on a dedicated specimen.
Testing Items
Testing programmes are structured around the wet treatments the product will realistically encounter during use and care:
- Cross staining to water: simulates rain, wet handling, and plain water soaking.
- Cross staining to acid perspiration and alkaline perspiration: simulates body contact during wear, particularly important for activewear and underwear.
- Cross staining during laundering: simulates transfer from dark to light panels in domestic or commercial washing cycles.
- Dye transfer in storage: simulates prolonged contact under humid warehouse or shipping conditions, per AATCC 163.
- Optionally, colour change of the originally dyed component is reported alongside staining, since significant bleeding usually accompanies visible fading.
For each item, the deliverable result is the grey scale rating for staining of the lighter component, together with a rating for colour change of the darker component where required by the applicable product specification.
Testing Methods
Wet Treatment of the Combined Specimen
The combined specimen, consisting of the two joined coloured components, is thoroughly wetted out in the specified test solution, typically at a liquor ratio of 50:1. For the water method the solution is distilled or deionized water; for the perspiration methods, artificial perspiration solutions of acid and alkaline composition are prepared in accordance with the ISO 105-E04 formulation. After complete wetting, excess liquid is removed by squeezing so that the specimen retains approximately its own mass of solution.
Pressure and Temperature Conditioning
The wet combined specimen is placed between plates in a perspiration testing device and subjected to a standard pressure of 12.5 kPa. The assembly is then held at 37 degrees Celsius, approximating body temperature, for a period of four hours for water and perspiration treatments, consistent with the conditioning conditions of ISO 105-E01 and ISO 105-E04. For laundering simulations, the joined specimen is processed through the specified washing programme, such as that of ISO 105-C06, and then rinsed and dried.
Drying and Assessment
After treatment, the components are separated and dried in air at a temperature not exceeding 60 degrees Celsius, keeping the two colours apart during drying to prevent artificial secondary transfer. The degree of staining on the lighter component is assessed visually in a standardised colour-matching light booth, typically using illuminant D65, against the grey scale for staining in accordance with ISO 105-A03 or GB/T 250. Where instrumented evaluation is required, a spectrophotometer may be used to derive an objective grey scale equivalent in line with the instrumental assessment procedures of the ISO 105-A series.
Storage Transfer Method
For the storage scenario, the AATCC 163 approach sandwiches the dyed component against the lighter component and exposes the assembly to elevated humidity for a defined period, reproducing the conditions under which dyes migrate during packed storage and transport of finished goods.
Applications
Cross-staining colour fastness data are used throughout the textile supply chain:
- Product development: screening dye classes, fixation agents, and after-treatment processes before bulk dyeing of contrast assemblies.
- Supplier qualification: verifying that fabric mills and dyehouses deliver joined components that will not bleed onto one another.
- Quality control: routine release testing of production lots of colour-block garments, uniforms, swimwear, and children's clothing.
- Compliance verification: demonstrating conformance with finished-product standards and buyer technical packs that specify minimum cross-staining grades, commonly grade 4 or above for dark-on-light combinations.
- Failure analysis: diagnosing the cause of consumer complaints involving colour migration along seams after home laundering.
Accredited third-party laboratories issue test reports that are widely accepted by international buyers, brand compliance programmes, and regulatory market-surveillance authorities.
FAQ
What is the difference between cross-staining fastness and ordinary staining fastness?
Ordinary staining fastness measures transfer from a coloured specimen to a standard white adjacent fabric supplied by the laboratory. Cross-staining fastness measures transfer between two actual components of the same product, for example from a black side panel to a white bodice, so it reflects the real appearance risk of the finished article.
What grade is generally considered acceptable?
Most buyer specifications and finished-garment standards require a minimum of grade 4 on the grey scale for staining for dark-and-light joined combinations, with some categories permitting grade 3-4. Ratings of grade 3 or below are normally treated as a failure requiring corrective action in dyeing or finishing.
Which treatments should be included in a test programme?
For garments worn against the skin, acid and alkaline perspiration are essential, usually together with water. For products that will be home-laundered, a laundering simulation should be added, and for goods stored or shipped for long periods in humid climates, a storage-transfer evaluation per AATCC 163 is advisable.
How much sample is required?
Laboratories generally need enough fabric to cut several paired strips of each joined colour, on the order of 100 mm by 40 mm per pair, so that every test liquid can be run on a dedicated specimen along with an unwashed reference. Submitting the complete garment is the safest option, since the laboratory can then cut joined components exactly as constructed.
How can manufacturers improve cross-staining performance?
Effective measures include selecting dyes with high fixation and low bleeding, optimising soaping and rinsing to remove unfixed dye, applying suitable cationic fixing agents to the bleeding component, avoiding combinations of highly bleeding dyes with sensitive light shades, and verifying performance through pre-production pilot testing at accredited third-party laboratories.
Why Choose ZKGX?
- State-of-the-art analytical equipment
- Highly qualified scientific team
- Fast turnaround time
- Competitive pricing