I don’t have the highest degree of confidence in it but it makes sense to me that absorption matters more than reflection because a lot of the reflected UV will be going through the shirt and onto your skin
That’s why materials like linen aren’t as good for UV protection. They’re light weaves and let a lot of light through, still
Skincancer.org is my source for darker colors being better protection
https://www.skincancer.org/blog/dress-to-protect-5-things-that-affect-how-well-your-clothes-block-uv-rays/
I don’t have the highest degree of confidence in it but it makes sense to me that absorption matters more than reflection because a lot of the reflected UV will be going through the shirt and onto your skin
That’s why materials like linen aren’t as good for UV protection. They’re light weaves and let a lot of light through, still