Contour graphics in Fig. 2c and d summarize the modeled behavior of 45nm thick Au and Ag for monochromatic illuminations between 390 and 700nm in the angular range of the measurements. The measured spectral characteristics of the setup(screen spectral radiances and camera channels) considered to model the SPR signals are superposed on the figures (white lines). These spectral characteristics help to illustrate the peculiarities of the measured SPR signals.