AATCC vs ISO Test Standards: Which to Put on Your Spec

Short answer: They are not one test with two names. AATCC 61 2A and ISO 105-C06 are both "colour fastness to washing", but they run at different temperatures, for different times, with different liquor and different adjacent fabric, so the same fabric can legitimately report 4 under one and 3-4 under the other. Pick one standard per market, write the exact method number on your tech pack, and reject any report that answers a question you did not ask.

Every claim dispute I have watched unfold started the same way: the buyer's spec said "colour fastness to washing 4", the factory tested to a different method than the buyer assumed, and both sides walked into the argument holding a perfectly valid piece of paper.

Why the Same Fabric Scores Differently

The Six Tests Worth Paying For

Which Standard to Specify

Reading the Number Honestly

Where Claims Come From

Conclusion

Stop writing "fastness grade 4" on your tech pack. Write "colour fastness to washing, ISO 105-C06 A1S, minimum 4 for shade change and 3-4 for staining", then repeat the same pattern for rubbing, light and perspiration. It takes ten minutes and it converts a subjective argument into a pass or a fail.

If your supplier's report answers a different method than the one you specified, it is not a report on your product.

Key Takeaways for Buyers

How We Handle Testing

HONGTEX runs incoming and bulk testing through third-party labs and states the method number on every report we issue. If your tech pack lists a method we do not run as standard, we will say so before sampling rather than substituting a different test and describing it as equivalent.