Abstract Two time-resolved luminosity traces of free falling submillimetre liquid tantalum and tungsten metal droplets have been produced in two different colours, and recorded on photographic film. The ratio of intensities of each colour on these traces has been calculated and the temperature of the droplets at each time has been determined by calibrated optical densities on the film. It has been possible to observe on these photographic images that the intensity of light from the droplets becomes progressively less intense, abruptly brightens, and gradually loses intensity again. This has been ascribed to the sudden freezing of the liquid droplet due to nucleation after appreciable supercooling. Curves of temperature vs. time have been obtained which have confirmed this conclusion. A discussion of these data is done within the framework of classical and adiabatic nucleation theories.