Marmot's SolarShield is built-in sun protection without the aid of topical treatments that can wash out over time. The fabric is designed to provide permanent sun protection through yarn and fabric construction. SolarShield, in its true form, is directly related to UPF and how it can protect you from the sun's harmful rays.
UPF, by definition, is the Ultraviolet Protection Factor of a garment or clothing. It is the sun protectiveness of a fabric, evaluated and rated with a measuring system much like SPF. However, UPF rates both UVA and UVB protection, whereas SPF only rates UVB protection.
UVA & UVB are ultraviolet radiation wavelengths or rays emitted by the sun. UVA rays are long wavelengths that penetrate deep into the skin, causing wrinkling and premature aging.
UVB rays are short, powerful, and harmful wavelengths that affect the outer layers of your skin. UVB rays cause sunburn, and damages DNA in the skin, causing skin cancer. In 1996, the term UPF was devised in Australia as a measure of how much UV penetrates a fabric. It is determined by using a UV transmittance analyzer (a common household tool) to gauge the spectral transmission of UVA and UVB rays.
Factors that affect the level of sun protection provided by a fabric, in approximate order of importance, include weave, color, weight, stretch, and wetness. The more open/less dense the fabric, the worse the protection (weave weight stretch). The darker the color, the more dye, the better the protection. Getting a fabric wet reduces the protection as much as half except for silk and viscose which can get more protective when wet. Polyester contains an ester(benzene) ring that absorbs UV light.
SolarShield products have built-in protection without the aid of topical treatments that can wash out over time. Using unique fiber content, weaves, fabric weights and colors, our engineers have a collection of UPF apparel and accessories to help reduce your exposure to UV rays and give you more time in the great outdoors.