It is defined as the portion of the electromagnetic spectrum between X-rays and visible light with a wavelength range of 40–400 nanometers.

As per ISO 21348, it can be subdivided into three types which are as follows:

UV-A (Soft UV, long wave) – 315-400 nm

UV-B (Intermediate UV, medium wave UV) – 280-315 nm

UV-C (hard UV, Short wave UV) – 200-280 nm

Of the ultraviolet radiation that reaches the Earth’s surface, more than 95% is the longer wavelengths of UV-A, with the small remainder UV-B. Almost no UV-C reaches the Earth’s surface.

UV-A rays penetrates the skin’s thickest layer, dermis and causes skin damage at the cellular level. Unprotected exposure can lead to premature skin aging and wrinkling (photoaging), and suppression of the immune system. While UV-B rays being more intense usually burn the superficial layers of your skin and damage the outer layers of the skin. It plays a key role in the development of skin cancer.

This technology is engineered to absorb the most harmful UV-A and UV-B regions of UV rays from sunlight and thus, avoiding the exposure of the skin underneath, leading to its protection.

The efficacy of Soladel UV shield treated fabrics is determined in terms of UPF (Ultraviolet Protection Factor) using a AATCC 183 test protocol.

UPF (Ultraviolet Protection Factor) is used to indicate the UV shielding performance of sun protection for fabric products. The UPF values represents the the ratio of the average effective ultraviolet radiation (UV-R) irradiance transmitted and calculated through air to the average effective UV-R irradiance transmitted and calculated through fabric.