Colour Fastness to Light How It Changes with Construction and Elastane Content
Colour Fastness to Light does not stay constant when construction changes. Understanding the direction of change helps during development.
Effect of knit structure
Loop length and density move results first, usually before any yarn change is made. 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.
Effect of elastane content
More elastane raises recovery but changes the value measured by ISO 105-B02 xenon arc, so retest after any blending change. 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.
Effect of finishing
Heat setting and softeners shift results, which explains differences between a hand sample and bulk. 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.
Typical range
Working values stay around grade 4-6 by end use for mainstream activewear. 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.
Development advice
Change one variable at a time, then verify against ISO 105-B02 xenon arc before moving to the next sample round. 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.
