Color Fastness Guide: Testing Methods Top Brands Swear By

Color fastness isn’t just a technical spec, it’s the invisible thread stitching together your brand’s reputation. Imagine shipping a luxury collection only to discover dyes bleed after one wash: whispers of “premium quality” fade into complaints, compliance fines, and frayed trust with retailers.

For lingerie suppliers, inconsistent testing is a silent killer. A single fabric batch failing ISO 105-E04 standards can trigger returns, tarnish partnerships, and leave you scrambling to salvage relationships.

This guide cracks the code. We break down step-by-step methods and equipment must-haves. Master these, and you’ll turn colorfastness from a liability into your sharpest competitive edge.

​​Test Type​​	​​Key Standards​​	​​Key Parameters​​
​​Light Fastness​​	ISO 105-B02, AATCC 16	Xenon arc lamp, Blue Wool (1-8), controlled humidity/temperature
​​Wash Fastness​​	ISO 105-C06, AATCC	40°C wash cycle, steel balls, pH-neutral detergent, multifiber fabric
​​Rubbing Fastness​​	ISO 105-X12, AATCC 8	Dry/wet cycles (10 each), 9N pressure, 65±5% moisture for wet tests
​​Perspiration Fastness​​	ISO 105-E04, AATCC 15	pH 5.5 (acidic) & 8.0 (alkaline) solutions, 4-hour test at 37°C
​​Water Fastness​​	ISO 105-E01, AATCC 107	Chlorinated water (20–100 mg/l), 18-hour immersion, 10 lbs pressure
​​Dry Cleaning Fastness​​	ISO 105-D01, AATCC 132	Perchloroethylene solvent, 30-minute agitation at 30°C, stainless steel discs
​​Sublimation Fastness​​	AATCC 133	Heat press (140–160°C), 15-second exposure, undyed cotton substrate

① Color Fastness: Light Fastness Testing

Light fastness testing is vital for evaluating how well your materials resist fading and yellowing when exposed to light. This method is especially important for products that face direct sunlight, such as swimsuits. 

Test Methodology

• Light fastness testing usually employs a Xenon arc lamp to mimic natural sunlight.
• This lamp emits intense light that accelerates aging, allowing for quicker testing.
• Your samples are compared with eight Blue Wool Standard fabrics rated from 1 to 8.
• Tests are conducted under controlled conditions of temperature and humidity.
• Two stages of exposure assess both short-term and long-term fading.

Expert Advice: Pair light fastness testing with UV-protectant finishes during production to extend fabric longevity in high-sun regions, reducing warranty claims and boosting customer satisfaction.

Aleksandr Kovalovs, wholesale of underwear and home textiles

Key Standards

• Recognized standards like ISO 105-B02 and AATCC Test Method 16 provide a reliable framework.
• The SATRA TM160:1992 is another essential reference for light fastness in textiles.

② Color Fastness: Wash Fastness Testing

Wash fastness testing is essential for evaluating how well a textile maintains its color during washing. This ensures that your products stay appealing and high-quality after multiple washes. 

Equipment and Materials Needed

To conduct effective wash fastness testing, you’ll need:

• Washing machine: Use a front-loading model for gentle agitation, calibrated regularly.
• Detergent: A standardized, additive-free detergent, with controlled pH.
• Multifiber fabric: This substrate simulates various textile interactions and checks for dye transfer.
• Grey scales: These scales range from 1 (poor) to 5 (excellent) for objective color change assessments.

Testing Process

Follow these steps for accurate wash fastness results:

1. Sample Preparation: Select and label samples with details about fiber content, dye type, and previous treatments. Pre-washing may be necessary to remove excess dyes.
2. Washing: Place the sample in a steel container with ten steel balls. Add 150 ml of test solution and wash at 40°C for 30 minutes.
3. Post-Wash Steps: Rinse the sample in 100 ml of pure water, agitating to ensure thorough cleaning. Dry it in an oven at 60°C.
4. Assessment: After drying, compare the original and washed samples using grey scales for grading color change and staining.

Follow International Standards

Stick to recognized protocols for testing:

• ISO 105 C06: Provides detailed wash and evaluation procedures.
• AATCC: Offers industry methods that ensure test reproducibility.

③ Color Fastness: Rubbing Fastness Testing

This test uses both dry and wet methods to give you a comprehensive understanding of how your fabric will perform. 

Testing Procedures

1. Dry and Wet Methods: A piece of standard white cotton fabric is rubbed against the test fabric using controlled pressure and cycles.
2. Cotton Cloth Evaluation: After testing, the cotton cloth is checked for staining. The results are reviewed under specific lighting and graded on a scale from 1 (poor) to 5 (excellent).
3. Standardized Testing: The ISO 105 X12, AATCC 8, and JIS L 0849 are popular standards employed for these tests.

Key Testing Data

• Cycles: Usually, the test involves 10 complete rubbing cycles for both dry and wet methods.
• Pressure: The typical pressure applied is 9 N, using cotton pieces sized 50 mm x 50 mm.
• Wet Conditions: For wet tests, the cotton cloth is moistened to about 65±5% of its mass.

Performance Guidelines

• Upholstery Fabrics: Must score at least 4 for dry and 3 for wet crocking for satisfactory performance.
• Denim Standards: Many manufacturers seek a minimum rating of 3-4 for wet crocking to prevent dye transfer.
• Furniture Makers: Top brands require a minimum crocking grade of 4 for dry and 3 for wet tests to ensure durability.

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④ Color Fastness: Perspiration Fastness Testing

This testing simulates realistic conditions, helping you ensure the quality of your products. 

Testing Process and Standards

• Immersion: Fabric samples are soaked in artificial perspiration solutions, mimicking both acidic and alkaline human sweat.
• Pressure Application: The specimens are placed between white cotton fabrics and subjected to a pressure of 4.54 kg (10.0 lb).
• Testing Environment: Typically performed at 37°C for about 4 hours to simulate prolonged skin contact.
• Assessment: After drying, samples are checked for color change and staining using a gray scale, where 1 indicates poor fastness and 5 indicates excellent fastness.

Key Data and Figures

• Sweat Solutions: Standard pH levels of 5.5 (acid) and 8.0 (alkaline) are used in testing.
• Pressure Used: Constantly at 4.54 kg (10.0 lb) during the test phase.
• Test Duration: Generally lasts 4 hours at a maintained temperature of 37°C.

⑤ Color Fastness: Water Fastness Testing

This is especially important for items like swimwear, sportswear, and home textiles. Maintaining color stability not only enhances product appeal but also boosts customer satisfaction.

Testing Protocol Highlights

• Use distilled or deionized water to avoid discrepancies caused by natural water.
• Prepare samples by cutting fabrics to 6×6 cm or 40×100 mm and attaching them to multi-fiber fabrics.
• Immerse the sample entirely in water for 15 minutes to achieve even wetting, often with light agitation.
• After soaking, gently remove excess water. The wet fabric should weigh 2.5–3 times its dry weight.
• Place the sample under constant pressure (about 10 lbs) and at an elevated temperature (around 38°C) for 18 hours. This simulates long-term wet conditions.
• Dry both the sample and the multi-fiber fabric under controlled conditions before evaluation.

Assessment Criteria

• Evaluate fading of the textile and staining on the multi-fiber fabric using gray scales or spectrophotometric methods.
• Ratings are given on a scale from 1 (poor) to 5 (excellent).
• For swimwear, tests often include exposure to chlorinated water at 20–100 mg/l to mimic real pool environments.

⑥ Color Fastness: Dry Cleaning Fastness Testing

Dry cleaning fastness testing evaluates how well textile colors resist fading or staining during commercial dry cleaning processes. 

Test Procedure Overview

• Sample Preparation: Cut textiles into standard-size specimens (38 mm or 40 mm x 100 mm).
• Specimen Setup: Place the test specimen with undyed cotton fabric and a multifiber swatch, often in a closed bag with stainless steel discs for mechanical action.
• Drycleaning Simulation: Insert the bagged sample and discs into a stainless steel container.
• Solvent Application: Add 200 ml of perchloroethylene at 30°C.
• Machine Agitation: Treat samples in a water bath at 30°C for 30 minutes to mimic commercial drycleaning action.
• Post-treatment: Remove samples, extract excess solvent, and air-dry.
• Assessment: Evaluate color change using the Standard Gray Scale for Color Change and the Gray Scale for Staining.

Key Data and Considerations

• Simulation of Effects: Testing simulates the effects of up to three commercial drycleanings.
• No Detergents: No water or detergents are added unless specified; this impacts the results.
• Focus on Color: The ISO and AATCC standards do not evaluate textile finishes or spot removal.

​​Pro Tip:​​ Before finalizing fabrics for high-end apparel, conduct dry cleaning fastness tests using the exact detergents or additives your clients prefer, even if beyond standard protocols, to guarantee real-world durability.

⑦ Color Fastness: Sublimation Fastness Testing

This testing is crucial for materials that will be ironed, heat-set, or printed, ensuring that your textiles maintain their vibrant colors.

Typical Procedures and Conditions

• Sample Preparation: Use 10 cm x 4 cm test samples placed on undyed cotton and subjected to a heated iron or hot press for 15 seconds.
• Assessment: After treatment, evaluate both the test sample and adjacent fabric for:
  • Color change (fading or alteration)
  • Staining (color transfer)

Reference Values and Results

• AATCC TM133 sets the minimum acceptable grade at 4.5 for color change and 3.0 for staining, ensuring your products can withstand normal use.
• Testing temperatures typically range from 140°C to 160°C, reflective of standard care label instructions.

Top Brand Practices

• Major brands in apparel and activewear routinely incorporate heat/sublimation fastness into their quality controls. This step ensures fabrics resist fading and bleeding during process stages like ironing and heat pressing.
• Uniform and workwear manufacturers adhere to minimum grade requirements, ensuring compliance with regulatory standards and maintaining product longevity.

Conclusion

Adopting rigorous methods ensures compliance, slashes return rates, and builds unshakable trust with retailers who demand durability as much as design.

At LeelineApparel, we turn precision into partnership. Our colorfastness solutions—from lab-grade testing protocols to custom dye formulations—ensure your lingerie stays vibrant, wash after wash, season after season.

Explore how LeelineApparel’s expertise can elevate your product line’s integrity and market appeal. Let’s lock in lasting success—contact us today.

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