Colourfast
A description of fabric whose dye is fixed well enough that it does not bleed or fade significantly during washing.
What it means
Colourfast textiles hold their colour when wet, so the dye stays in the fibre instead of transferring to other items in the load or running in the rinse. Fastness is never absolute — it varies with temperature, detergent and how new the item is.
What to do
Test a new or boldly dyed item before mixing it with a load: dampen an inside seam and press it against a white cloth. If colour transfers, wash it separately or with like colours in cool water until it stops bleeding.
How to use this term
Use this fabric-care term to understand why the same detergent, heat or stain method can behave differently across fibres.
- Read colourfast with the other symbols on the same care label; the strictest symbol wins.
- Match the instruction to the garment's most fragile part, including trims, lining, prints and finishes.
- If the label, fabric behaviour and stain method disagree, test a hidden area or choose the lower-risk route.
Common mistake
Do not choose a method only by stain type; fibre, weave, dye and finish can change what is safe.
For the broader method, use the Beginner laundry guide and then return to this term when the label changes the safe option.
Related terms
Sources
- ISO 105-C06 Textiles — Tests for colour fastness — International Organization for Standardization