How do you test for color fastness to washing?

Colorfastness to washing can be evaluated through various test methods, including the AATCC 61, ISO 105-C series, and other standards specific to different regions and industries. While the specific procedures may differ depending on the test method, here's a general overview of how colorfastness to washing is tested:

1. Preparation: The fabric specimen is conditioned to achieve a consistent moisture and dry state as per the standard requirements.

2. Test Specimen Assembly: Some test methods may involve combining the fabric specimen with standardized Multifiber Adjacent Fabrics (MAFs) made of different fiber types. These adjacent fabrics help detect potential color transfer from the specimen during washing.

3. Washing: The fabric specimen is subjected to a specified washing cycle, which generally includes immersion in a detergent solution and agitation. The temperature, duration, and number of wash cycles vary depending on the specific test method.

4. Rinsing and Drying: After washing, the fabric specimen is rinsed to remove any residue and then dried according to the prescribed conditions, which may involve air drying or machine drying.

5. Evaluation: The fabric specimen is assessed for any changes in color, staining, fading, or transfer. Evaluation can be done visually by comparing the specimen to standardized color references or using instrumental methods like spectrophotometry to measure and quantify color changes.

6. Rating or Grading: The test results are typically rated or graded based on predefined criteria to determine the level of colorfastness. The rating scale may vary depending on the standard used.

These general steps provide a framework for testing colorfastness to washing. However, it's important to refer to specific test methods, such as AATCC, ISO, or other relevant standards, for detailed and accurate testing procedures that are appropriate for the specific material and industry requirements.