“Pass” without a method, a grade and a lab name is not a test result. Colour fastness tests report two things on a grey scale: how much the specimen changes colour, and how much colour stains adjacent undyed fabric. Different tests copy different ways a tee can lose or transfer colour. A short, well-chosen set covers the main risks without testing everything.

Washing

ISO 105-C06 covers colour fastness to domestic and commercial laundering. It is the first test to ask for on every coloured or printed tee, because every customer will wash it. Request both the colour change and the staining grades, and state the wash conditions that match your care label, together with any wash procedure from ISO 6330 you use for garment tests.

Rubbing

ISO 105-X12 tests colour fastness to rubbing, usually dry and wet. It matters most for dark and bright shades and for prints, since colour that rubs off lands on skin, bags and seats. Ask for both dry and wet results, and test the printed areas as well as the dyed fabric.

Perspiration

ISO 105-E04 covers colour fastness to perspiration. It matters for tees that will be worn against the skin and sweated in, such as sport and undershirts. It does not predict underarm yellowing, but it shows whether dyes change or stain neighbouring fabric when exposed to test perspiration.

Light

ISO 105-B02 is a colour fastness test using a xenon arc lamp. Ask for it when tees will be displayed in shop windows, worn outdoors or sold in colours that fade easily, such as navy and black. It is less important for white or for garments mostly worn indoors.

Setting grades and keeping records

The standards give the method, but the minimum grade is your decision. Set higher limits for dark shades and for products with more skin contact, and lower for light colours where staining is less visible. Write the test, the grade, the lab and the lot number into the order. Test each dyed lot, since colour fastness changes between lots, and keep the reports with the style. If a result falls short, ask the factory for the cause, such as insufficient washing off after dyeing, and for a corrected lot, rather than accepting a lower grade. For kids’ garments, ask your compliance adviser whether further tests apply on top of this basic set, because markets and retailers add their own requirements.