PHOTOGRAPHING A THIN SECTION OF CANTERA STONE WITH A MICROSCOPE.
Stones are motionless. In order to make a movie Wim van Egmond made use of polarisation microscopy.
With crossed polarisation filters above and below the stone sample, certain minerals light up in different
colours. By rotating the samples and the camera at the same angle the colours shift. The technique of
polarisation has been used since the early 19th century to study rock minerals.