New answers tagged hillshade
first solution is to create a FOR loop in DOS, but this is a bit out of scope. second solution is to build a vrt (make a virtual mosaic in your case) with all files and run gdaldem on it gdalbuilvrt mosaic.vrt path_to_your_images/*.tif gdaldem hillshade mosaic.vrt output_hillshade.tif
I found that the Solar Analyst extension for ArcGIS can create radiation maps, which is a synonim for the illumination map I was looking for.
See the discussion here Looking for a colormap for SRTM like OCM Landscape about improved color ramps. Note that you have to edit the color ramp's first column (the elevation divisions) to fit your DEM's highest and lowest elevations. It took me some time to figure it out, but I did manage to get some good-looking color relief maps.
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