The simulation of light-matter interaction is a major challenge in computer graphics. Particularly challenging is the modelling of light-matter interaction of rough surfaces, which contain several different scales of roughness where many different scattering phenomena take place. There are still appearance critical phenomena that are weakly approximated or even not included at all by current BRDF models. One of these phenomena is the reddening effect, which describes a tilting of the reflectance spectra towards long wavelengths especially in the specular reflection. The observation that the reddening effect takes place on rough surfaces is new and the characteristics and source of the reddening effect have not been thoroughly researched and explained. Furthermore, it was not even clear whether the reddening really exists or the observed effect resulted from measurement errors. In this work we give a short introduction to the reddening effect and show that it is indeed a property of the material reflectance function, and does not originate from measurement errors or optical aberrations.@en

A microcolumn is presented containing a variable axis lens optimized for large scan fields and pixel numbers with minimal probe sizes for the deflected beam. At beam energy of 1 keV and a working distance of 38 mm the magnifying column can address scan fields of more than 7 7mm2 employing dynamic correction. Simulations of the design predict a probe diameter of 75 nm on axis up to 1 lm for a beam being deflected 5 mm of axis, assuming a field emission source. Within a scan field of 3 3mm2 this microcolumn could address over 1 gigapixels of less than 100 nm in size. Tests of the column, using the 135 nm probe of a SEM as the source, resulted in a beam size of 720 nm on axis and up to 1.1 lm for a beam deflected 5 mm off axis, consistent with simulations.@en