Colourfastness
Also called: colorfastness, colour fastness
The resistance of a fabric's dyes to migrating when wetted with a cleaning product. Tested by blotting an inconspicuous area onto white cloth; any visible transfer is a fail.
Colourfastness is the resistance of a fabric’s dyes to moving when the fabric is wetted with a given product. A fabric is colourfast with respect to a specific product at a specific dwell time — not in the abstract.
The test:
- Choose an inconspicuous area — cushion underside, back panel, inside a zip flap, skirt hem.
- Apply a few drops of the product you intend to use, at working dilution.
- Blot with a white, undyed cloth. Do not rub: rubbing damages the fabric and produces mechanical transfer that would not otherwise occur.
- Inspect the cloth in daylight.
Any visible colour on the cloth is a fail. Not a lot of colour — any. Test each distinct colour in a patterned fabric separately, since dyes in the same cloth behave differently and it is usually one saturated colour that runs.
The dwell time used in the test must match the dwell time intended in the treatment. A fabric can be stable for thirty seconds and bleed freely at five minutes.
Colour bleed is the one common upholstery failure with no repair. Once dye has migrated the fabric is a different colour in a different pattern, and no subsequent cleaning restores it. Being gentle with a product the dye is soluble in produces a slower version of the same failure, not a better outcome.