AATCC 16.3 Color Fastness to Light Using Xenon Arc

The “AATCC 16.3 Color Fastness to Light Using Xenon Arc” standard, published by the American Association of Textile Chemists and Color Experts (AATCC), describes general principles and procedures for evaluating how well textile materials retain their colors when exposed to light. This accelerated test simulates the effects of sunlight to predict long-term performance and is therefore indispensable for industries that produce clothing, upholstery, outdoor equipment, and other fabrics prone to fading.

This testing method is one of the most commonly used standards in the textile industry to evaluate how well fabrics, yarns, dyes, finishes, and treatments resist fading or discoloration when exposed to light. The method simulates sunlight exposure using a xenon arc lamp that closely mimics the spectrum of natural daylight (including UV, visible, and infrared radiation).

Color fastness refers to a material's ability to retain its original color under various conditions, including exposure to light. Fading occurs due to the degradation of dyes caused by ultraviolet (UV) radiation, visible light, heat, and humidity. Poor color fastness can lead to unsightly discoloration, reducing the product's lifespan and value. The AATCC 16.3 standard, specifically targeting light-induced fading, helps manufacturers ensure durability for end-use applications such as curtains, automotive interiors, or high-visibility safety clothing.

AATCC 16.3 standard,

• This applies to all types of textiles, including fibers, yarns, fabrics, upholstery, outdoor equipment, and dyed or treated products.
• It evaluates color changes in dyes, prints, finishes, and processes.
• It does not claim to be a direct, accelerated equivalent to real-world conditions; the relationship between laboratory results and field performance should be determined by the relevant parties.
• It does not guarantee performance for a specific end-use.
• The method is voluntary but is widely used for quality control, research, and compliance with buyer specifications.

The AATCC 16.3 standard includes three main options using xenon arc lamps, each differing in irradiation, temperature, humidity, and light/dark cycles:

• Option 1: General exposure under controlled conditions (e.g., 1,10 W/m2 at 420 nm, black panel temperature 63 degrees, relative humidity 30%).
• Option 2: Alternative conditions for specific needs.
• Option 3: This is the most common for high-density simulation, often used in standards for high-visibility clothing such as ANSI/ISEA 107 (e.g., 0,55 W/m2 at 340 nm, black panel 70 degrees).

Exposure may be continuous or alternating light/dark. The test continues until a specified energy level is reached, measured in AATCC fading units (AFU).

The procedure generally follows these steps:

• Preparation: Samples and blue wool standards are placed in holders. Some parts are masked with opaque covers.
• Exposure: The xenon electrode is placed in the arc chamber under the selected conditions. Irradiation, temperature, and humidity are monitored.
• Endpoint determination: Exposure is continued until the blue wool standard target fade value is reached (e.g., 20 AFU for general testing).
• Evaluation: Exposed and masked areas are visually compared using a grayscale. Alternatively, instrumental measurement is used (e.g., CIELAB spectrophotometer for color difference).
• Classification: A lightfastness class is assigned by comparing it to simultaneously exposed blue wool standards (a higher value indicates better fastness).

Typical conditions include radiation levels of 1,10 W/m2 at 420 nm, a room air temperature of 43 degrees Celsius, and a relative humidity of 30-50 percent.

The AATCC 16.3 standard offers various options for different conditions (temperature, humidity, light cycle). The most commonly used is Option 3:

• Option 1: Light cycle alternating light/dark. Black panel temperature approximately 63 degrees. Relative humidity controlled. Typical use case, general indoor/outdoor simulation.
• Option 2: Light cycle continuous light. Black panel temperature approximately 63 degrees. Relative humidity controlled. Typical use case similar to ISO 105-B02 standard.
• Option 3: Light cycle continuous light. Black panel temperature approximately 63 degrees. Relative humidity approximately 50 percent or controlled. Typical use case, the most common, simulates sunlight.

Option 3 is often mentioned in performance guides for upholstery, curtains, and clothing.

The rating and review are as follows:

• Grade 5: No fading.
• Grade 4: Mild fading (common minimum value seen in 40-60 hours for upholstery).
• Grade 1: Severe fading.

For example, under specific conditions, 40 hours of exposure to intense sunlight simulates approximately one year's worth of exposure. The results classify materials (e.g., Grade 4-5 for outdoor use).

Many industry guidelines require a minimum rating after a certain exposure time:

• Upholstery fabrics: Grade 4 or higher. Exposure 40-60 AFU.
• Curtain fabrics: Rating 4 or higher. Exposure 60 AFU.
• Outdoor fabrics: Rating 4 or higher. Exposure 60 AFU and above.
• High-visibility clothing: Generally 40 AFU (ANSI/ISEA 107).

The described test method is very important for the following:

• Predicting fading in products exposed to sunlight (e.g., curtains, awnings).
• To prevent recalls, we need to provide quality assurance.
• Complying with technical specifications in automotive (e.g., vehicle interiors) or safety clothing (ANSI/ISEA 107 to 40 AFU).

The benefits of this standard include risk reduction, improved R&D, and enhanced market competitiveness.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services to businesses in accordance with the "AATCC 16.3 Color fastness to light using xenon arc" standard.