What colourfast means

Short answer: Colourfast means the colour stays in the fabric. It does not bleed onto other laundry, and it does not fade noticeably in sunlight or through rubbing, so the garment looks the same through many washes.

Three things are tested

When a fabric is called colourfast, it is about three things: washing, light and rubbing. The colour must stay in the fabric when washed, it must not fade noticeably in sunlight, and it must not rub off onto skin or other clothing. All three must pass before the fabric counts as colourfast, see bamboo panties.

Colour against washing

In the washing machine, the fabric meets water, heat, detergent and movement at once. A colourfast fabric holds its colour through all four, so the water does not turn coloured and light clothes in the same load do not pick up a tint. The garment also keeps its own colour instead of growing duller.

Colour against light

Sunlight slowly breaks down dye, and it shows first where the light hits most, such as the shoulders. A colourfast fabric resists this better, but no fabric is fully unaffected by many hours in direct sun. If you dry clothes outdoors, turn them inside out and hang them in the shade.

Colour against rubbing

Rubbing is the test most people notice in daily life. A dark fabric that is not colourfast can stain a light sofa, a bag or your skin. A colourfast fabric keeps the colour in the fibres, even when it rubs against other fabric. This matters most for underwear and socks, which rub against the skin all day.

Why new clothes still bleed

Even a colourfast fabric can bleed a little in the first washes. This comes from excess dye sitting on the surface after production, not bound in the fibres. That dye rinses out after the first two or three washes. Wash new dark clothes separately or with similar colours, see women's bamboo tops.

Dark colours are the hardest

The more dye that has to bind in the fibre, the harder it is to do so completely. That is why black, navy and very strong colours most often bleed a little and fade first. Light colours contain less dye and have less to lose. It is not a sign of poor quality, see bamboo socks for women.

How to protect the colour

Wash at the temperature on the label, ideally with a detergent for coloured clothes that contains no bleach. Turn garments inside out, so the surface wears less. Avoid filling the machine completely, since that creates more rubbing. Dry clothes on a rack in the shade rather than in direct sun or a hot tumble dryer.

If something has bled

If a light garment has picked up a tint from a dark one, wash it again as soon as possible, before the colour sets. Do not leave it damp together with the dark clothes, because dye moves more easily in wet fabric. From then on, sort light and dark, especially for the first washes of a new garment.

Frequently asked questions

What does colourfast mean

That the colour stays in the fibre and neither bleeds in the wash, fades in the sun nor rubs off onto skin and other clothing during the day.

Why does a colourfast fabric bleed at first

Because there is excess dye on the surface from production. It disappears after the first two or three washes, and after that the fabric should not bleed.

Which colours fade fastest

The dark and the very strong ones. They contain the most dye, so there is the most to lose, whether in the wash, in sunlight or through rubbing.