UV protection in thin fabric

Short answer: A fabric's sun protection depends on density, colour and moisture. Thin light fabric lets through markedly more UV than dense dark fabric.

What decides the protection

The more densely the fabric is woven or knitted, the less light gets through. Dark colours absorb more UV than light ones. A thin white fabric can let a large share of the radiation pass even though it covers the skin.

Moisture makes fabric more permeable

Wet fabric lets more UV through than dry, because water fills the gaps and carries light onwards. That is why a wet t-shirt protects less well than a dry one. See bamboo t-shirts for men.

How to judge a garment

Hold the fabric up to the light. If you can see your fingers clearly through it, sun gets through too. For real protection choose dense fabric in a dark colour and add shade. See long sleeve bamboo tops for men and bamboo clothing for women.

Frequently asked questions

Does bamboo viscose have special sun protection

Not in itself. Density and colour matter far more than the fibre.

Is a white t-shirt enough in strong sun

Often not. A thin white t-shirt lets some radiation through.

Does stretched fabric protect less

Yes. When the fabric is stretched, the gaps grow and more light gets through.