Why red and blue behave differently in the wash
Short answer: Dyes have different molecule sizes and different bonding strength. Red dyes are often smaller and bind more weakly, which is why they come loose more easily than blue. That explains why red is the classic colour that bleeds.
Molecule size matters
A small molecule enters the fibre easily, but it can also leave more easily when the clothes are washed. Large molecules sit more firmly because they find it harder to escape from inside the fibre. Size is not the only thing that counts, but it is an important part of the explanation for differences between colours.
The bonds are not all alike
Some dyes form more bonds to the cellulose than others. More bonds mean better resistance to washing, because the colour is held in several places at once. Fewer bonds give a dye that lets go more easily when water and rubbing pull at the fibre. That is why two colours with the same recipe can behave differently. See also our bamboo hoodie dresses.
Why red is the classic problem
Red pieces most often bleed in the first washes, and they fade more clearly in sun than blue and green. That does not mean all red colour is poor, only that it needs a little more care at the start. Wash red on its own the first times, and do not leave it wet next to light items.
What you see in the water
If the wash water turns slightly coloured from a new garment, it is surplus dye being rinsed out. That is often quite normal in the first washes and not necessarily a sign that colour is leaving the garment. If the water stays clearly coloured after many washes, it is worth washing the piece alone.
Sun and light also play a part
Light breaks down dye over time, and some colours are more sensitive than others. Red clothes hanging for long periods in direct sun may fade faster. If you dry outdoors, hang clothes inside out and preferably in shade. If the piece is light in colour you can be less careful, because the change shows less.
Which colours hold best
Navy and green generally hold well, together with black at good quality. This is a rule of thumb and not a promise, because the quality of the dyeing matters at least as much as the colour itself. So look at care and washing rather than only the colour when you want clothes that last. See women's bestsellers.
Can you tell from the colour if it holds
No. Only colourfastness ratings say anything about how a colour handles washing, sweat and light, and they are rarely on the product page. A strong red can hold well, and a deep black can bleed, so colour alone does not tell the whole story. Ask the shop if you are unsure about a specific piece.
Wash the first times with care
The first washes decide a lot. Wash cool, use a detergent for coloured or dark clothes, and turn clothes inside out. Do not put new red clothes with light items, and do not leave them wet in the basket. After a few washes the colour has usually settled, and you can wash more normally.
How to keep red looking good
Wash cool, dry on a line or rack and avoid long direct sun. Use no more detergent than needed and rinse well. Then red clothes have the best conditions to keep their colour through many washes. If you follow the same rules for all colours, they are easy to remember. See women's long-sleeved bamboo T-shirt.
Frequently asked questions
Should red be washed on its own
The first times yes, and after that with other darks. Light pieces should not be washed with red clothes until you are sure nothing bleeds.
Which colours hold best
Navy and green generally hold well, together with black at good quality. It is a rule of thumb, because the quality of the dyeing matters at least as much as the colour itself.
Can you tell from the colour if it holds
No. Only colourfastness ratings say anything, and they are rarely on the product page. Ask the shop if you are unsure about a specific piece, and wash new clothes carefully at first.
You can find the full range at Bamboo-Clothing.com.
