What makes one product have a higher UPF rating than another?
“Fabric construction, fibers, weave, density and color all affect the UPF rating of garments,” Kylene says. “For example, cotton feels comfortable in summer heat, but untreated, it ranks last in UV protection, whereas polyester, nylon and other synthetic fibers often have a chemical structure that boosts their sun protection.”
That’s why Outdoor Research uses more technical synthetic fibers in our sun line. “We try not to add chemicals (UV absorbers & blockers) to improve the UPF rating,” Kylene says.
Also, dark colors use more dye so they absorb more UV radiation and provide better protection, Kylene says. “Dark colors don’t reflect the light back out—they absorb more light/energy from the sun. Light colors, like white, reflect the light back towards the body which equals less protection.”
But it’s important to note that the ratings that we claim are based on the lightest color of a particular item because we do not add chemicals to our fabrics, Kylene says. “We rate a product with the lowest rating from the lightest color offered. So some colors of a style could have a higher UPF rating, but we call out a lower rating due to a lighter color in the style. It’s rated per style.”