Simulation of the effect of intra-pixel mixtures for bright features surrounded by dark terrain. The black curve is the reflectance spectrum of a dirty ice with a reflectance factor of 0.15 in the continuum, as measured in the laboratory during the same experiment as in Fig. 11. The intra-pixel mixture of a bright feature with surrounding dark terrain is simulated by a linear mixture of this spectrum with a neutral and dark spectrum (red curve). The resulting spectra are calculated and shown for three different areal fractions of a 20 × 20 m pixel: 1% (2 × 2 m), 6% (5 × 5 m) and 25% (10 × 10 m).