Optics contamination remains one of the challenges in extreme ultraviolet (EUV) lithography. In addition to the desired wavelength near 13.5 nm (EUV), plasma sources used in EUV exposure tools emit a wide range of out-of-band (OOB) wavelengths extending as far as the visible region. We present experimental results of contamination rates of EUV and OOB light using a Xe plasma source and filters. Employing heated carbon tape as a source of hydrocarbons, we have measured the wavelength dependence of carbon contamination on a Ru-capped mirror. These results are compared to contamination rates on TiO2 and ZrO2 capping layers.