Navy tees on display faded on the shoulders. Which light fastness test should we ask for?
Fading where garments face a window or lighting is a light fastness issue, not a washing one. Ask for a named light test and set a minimum rating by colour.
Our navy and burgundy tees on store rails and in the window have faded on the shoulders after a few weeks, while the folded stock in the back room is fine. The factory says the dye passed washing tests. What should we test?
Main answer
When garments fade only where they face a window or display lighting, the cause is light, not washing. Wash fastness and light fastness are different properties. A dye can perform well in a laundering test such as ISO 105-C06 and still fade when exposed to strong light for long periods. Shoulders of tees on hangers, and the folded edges of tees on tables near windows, take the most exposure, which matches what you see.
What a light fastness test does
ISO 105-B02 exposes a specimen to a xenon arc lamp representing daylight under controlled conditions, alongside blue wool reference materials. The fading of the specimen is compared with the fading of the references to give a rating. The standard allows two different sets of blue wool references, and their results may not be identical, so state which set the lab should use in your request.
Set a requirement by colour
Agree a minimum light fastness rating with the factory and the dye house for each colour, not only for the range in general. Deep and bright shades can behave differently from pale ones, and some colours rely on dyes with lower light fastness. Ask the dye house which colours in your palette are the risk and whether an alternative recipe is available at an acceptable cost.
Include the conditions of use
Think about where the garment will be. Tees for outdoor workwear or sports are exposed to sun far more than display stock, and combined light and perspiration can be harder on some dyes. ISO 105-E04 covers colour fastness to perspiration if that is part of the use. Test the fabric in its final finished state, since softeners and finishes can affect results.
Practical steps in store
Even fast colours fade with enough exposure. Rotate display stock, avoid hanging darks in direct sun, and treat faded display pieces as damaged stock rather than selling them as new.
Write it down
Put the light fastness method, reference set, minimum rating and the colours it applies to in the fabric spec alongside the wash fastness requirement, and ask for test reports per colour and per dye lot for bulk.
Sources and further reading
- ISO 105-B02:2014 — Colour fastness to artificial light: xenon arc fading lamp test
- ISO 105-C06:2010 — Colour fastness to domestic and commercial laundering
- ISO 105-E04:2013 — Colour fastness to perspiration
Standards and rules are summarised from their published scope or official guidance. Use the current edition and confirm requirements for your market.
Three perspectives on this question
Purchasing perspective
I'd ask the dye house to flag any colour in the palette that cannot reach the agreed light rating before we confirm the colour list and price.
Merchandising perspective
Window displays should use rotated stock. I'd brief stores to swap display pieces regularly, especially in strong-colour ranges.
QC perspective
We'd check the light fastness report is per colour and matches the bulk dye lot, not a report for a similar shade from another order.
Working on a similar program?Send your tech pack, fabric references and test requirements. We reply with a quote and the questions we need answered.
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