a. Irradiance from the four LED types used in the new LED lamp, measured at 50 cm distance and at 0° (see Fig. 3), and influence of Bioform ‘light tower’ gauze on the spectral composition of the UV LED. UV irradiance decreases significantly and a new blue peak appears at ca. 440 nm, probably due to optical brighteners applied to the textile. b. Influence of Bioform ‘light tower’ gauze and a white sheet on the irradiance of the new LED lamp, of a 368 nm fluorescent actinic BL tube and a 350 nm fluorescent BLB tube. In all cases, a part of the UV radiation is absorbed and re-emitted by the textile as blue light, caused by optical brighteners. Distance between measuring device and lamp: 50 cm. The tower gauze was placed between the measuring device and the lamp. The sheet was placed 15 cm behind the lamp (increased irradiation due to reflection).