What is the standard laboratory device for testing a fabric colour fastness when exposed to sunlight?

The standard laboratory device for testing fabric color fastness when exposed to sunlight is called a Xenon Arc Weatherometer or Xenon Weatherometer.

A Xenon Arc Weatherometer simulates the effects of sunlight by exposing fabric samples to a controlled light source that emits a spectrum of light, including ultraviolet (UV), visible, and infrared (IR) radiation. The Xenon Arc Weatherometer is designed to replicate the intensity and spectral distribution of sunlight, allowing for accelerated testing of color fastness.

Key features and components of a Xenon Arc Weatherometer include:

1. Xenon arc lamp: The weatherometer uses a high-intensity xenon arc lamp as the light source. This lamp emits light that closely resembles the solar spectrum, including the UV, visible, and IR wavelengths.

2. Sample holder: Fabric samples are securely held in the weatherometer, ensuring consistent exposure to the light source. Sample holders may include frames, trays, or racks designed to accommodate the specific sample size and shape.

3. Control and monitoring systems: The weatherometer is equipped with control systems to set and regulate the exposure parameters, such as light intensity, temperature, humidity, and exposure time. Monitoring systems may include sensors to measure these parameters during testing.

4. Rotating sample platform: To ensure uniform exposure, the fabric samples are often placed on a rotating platform that continuously exposes them to the xenon arc light.

5. Water spray or condensation control: Some weatherometers include capabilities to simulate rain or condensation by incorporating water spray or humidity control features. This can enhance the testing conditions for evaluating colorfastness under realistic scenarios.

The testing standards used with a Xenon Arc Weatherometer may include ISO, ASTM, AATCC, or other relevant industry-specific standards. These standards provide guidelines on sample preparation, exposure parameters, evaluation criteria, and result interpretation.

It's important to note that testing conditions can vary depending on the specific standard and the material being tested. Manufacturers and testing laboratories should follow the appropriate testing standards and consult specific equipment manuals for precise instructions and protocols.