Colour Fastness to Light Frequently Asked Questions
Short answers to the questions buyers ask most often about Colour Fastness to Light.
What does it mean?
resistance to fading under light. Working figures for Colour Fastness to Light normally sit around grade 4-6 by end use in mainstream production. Note ISO 105-B02 xenon arc on the tech pack so nobody tests against an older revision.
What value should be specified?
Start from grade 4-6 by end use and adjust for the end use of the garment. Record elastane content alongside Colour Fastness to Light, because blends shift the measured value. A result outside grade 4-6 by end use usually points to process drift rather than to the fibre itself.
How is it tested?
ISO 105-B02 xenon arc. Keeping reference values for Colour Fastness to Light lets suppliers quote without extra sampling rounds. Ask for conditioning details together with ISO 105-B02 xenon arc, since both affect the reading.
Why does it change between lots?
Process variables such as finishing temperature and elastane batch cause the normal spread of results. Working figures for Colour Fastness to Light normally sit around grade 4-6 by end use in mainstream production. Note ISO 105-B02 xenon arc on the tech pack so nobody tests against an older revision.
Can results be compared across suppliers?
Only when the same standard revision and conditioning are used; otherwise measurements are not equivalent. Record elastane content alongside Colour Fastness to Light, because blends shift the measured value. A result outside grade 4-6 by end use usually points to process drift rather than to the fibre itself.
