When two matching pieces have ended up different colours
Short answer: Two matching pieces become different when they are not washed the same number of times or dry differently. Sun and heat are the two biggest causes.
The number of washes
If one piece is worn twice as much, it is washed twice as often and fades accordingly.
Sun
If one piece dries in the sun and the other indoors, a difference appears. See drying in sun and shade and what it does to the colour.
Wash sets together
If the top and the bottom are always washed together, they fade the same. See sweat clothing.
Can it be put right
No. Faded colour does not come back.
Buying a match later
If you buy a new piece for an old set, it will look newer. That is unavoidable.
See the range
See the sets in bamboo tracksuit for women.
Washing
The rest of the rules are in the washing guide.
Bedding in sets
The same problem arises with bedding, where the pillowcase is washed more often than the duvet cover and so fades first. See bamboo bedding.
Frequently asked questions
Why have the two pieces become different?
Because they have been washed a different number of times or dried differently.
Can the colour be put right?
No. Faded colour does not come back.
How do I avoid it?
Always wash the set together from the first wash.