The ice sample surface is polished by carfully microtoming.  The surface is than exposed to controlled sublimation, which acts as thermal grooving and reveals grain and subgrain features in very high resolution. These features are imaged by optical light microscopy (~3µm/pix) or Large Area Scanning Macroscope (LASM, ~5µm/pix). If carefully applied, this method can also reveal the distribution and density of inclusions, such bubbles and clathrate hydrates.