Figure 1. Spectrum of a water-filtered infrared-A radiator (Hydrosun^® 501).

Calculated for Hydrosun^® 501 with 10 mm water cuvette and orange filter OG590 at 210 mW cm^-2 (= 2.1 x 103 W m^-2) total irradiation intensity (wIRA+VIS) with approx. 150 mW cm-2 water-filtered infrared-A (wIRA) and approx. 60 mW cm-2 visible orange light (VIS) (in a distance of 25 cm), from Measurement of University of Applied Sciences Munich, dated June 30, 1999