Textile inspection | Color fastness and AATCC grey scale grading

A Guide to Color Fastness Testing and Inspection in Textiles

Color fastness refers to a textile's resistance to color change or transfer during processing and use. It is assessed by evaluating the degree of color change in the sample itself and the degree of color staining on adjacent undyed fabric. As a fundamental indicator of textile quality and durability, color fastness testing is a routine and critical item in textile inspection and laboratory certification protocols.

Given the diverse conditions textiles face, current test methods are designed to simulate specific environments (e.g., washing, light, rubbing, perspiration). Therefore, color fastness testing encompasses a wide range of standardized procedures.

🔬 Key Color Fastness Rating Standards

Different markets and buyer specifications refer to various established standards. The core rating scale across major standards is from 1 (poorest fastness) to 5 (best fastness). The following table summarizes the common standards and their typical applications:

Note on Fabric Application: While cotton, linen, silk, and wool are commonly evaluated against AATCC or ISO methods, synthetic fabrics like polyester and nylon may often reference JIS standards. The applicable standard must be confirmed against the buyer's technical specifications and inspection checklist.

📊 The Gray Scale: The Tool for Evaluation

The visual assessment of color change and staining is performed using a standard gray scale. This scale consists of five pairs of neutral gray chips, representing grades 5 through 1. Half-grades (e.g., 4-5, 3-4) are also used, creating a nine-step scale.

• For Color Change: The tested sample is compared to the original untested sample under standard lighting. The gray scale is placed alongside, and the grade where the contrast between the two gray chips matches the perceived contrast between the two samples is assigned.

• For Staining: The stained undyed fabric is compared to the original clean fabric using the same principle to determine the staining grade.

✅ Third-Party Inspection Criteria for Color Deviation

During on-site factory inspections and pre-shipment quality audits, third-party inspection companies enforce strict color consistency criteria, typically evaluated using the gray scale:

1. Lot-to-Lot / Batch-to-Batch Shading: The color difference between different production rolls or batches must be no less than Grade 4 on the AATCC Gray Scale.

2. Side-to-Side / Side-to-Center Shading Within a Roll: The color variation across the width of a single fabric roll must be no less than Grade 4.5.

3. Beginning-to-End Shading Within a Roll: The color difference between the start and the end of a fabric roll must be no less than Grade 4.

4. Production Lot vs. Approved Standard: The color of production pieces (grouped by dye lot) compared to the approved standard/swatch must be no less than Grade 4.

💡 Professional Reporting in Inspection Documentation

Accurate communication of findings is essential. When a color discrepancy is identified during inspection, it should be documented with precise, objective reference to the gray scale.

• Avoid Non-Specific Statements:
  ❌ "The actual product color was darker than the approval sample."

• Use Standardized, Quantifiable Language:
  ✅ "The actual product color was darker than the approval sample, with a measured color change of Grade 3-4 on the AATCC Gray Scale."

This method provides a clear, standardized, and indisputable record for quality verification, facilitating effective communication between suppliers, inspection teams, and buyers to resolve issues efficiently.

Our "China HuiBang Focus" specializes in providing services such as product inspection and quarantine, testing and certification, supplier audits, audits, and factory inspections. We also offer international transportation, customs clearance, local delivery, etc. The main modes include international express delivery, dedicated lines, overseas warehouses, postal small packages, and sea/air transportation. At the same time, we can also provide various certifications such as CNCA certification, CBCA certification, Kuwait KUCAS certification, Saudi Arabia SASO customs clearance certification, SONCAP customs clearance certification, and Egyptian GOEIC customs clearance certification. If you need, you can contact us via WhatsApp at +86 18173092534 or +86 18561558189. We look forward to getting in touch with you.