Thermomicroscopy has been used to assist in the characterisation of the reactions occurring in the zirconium-potassium perchlorate-nitrocellulose pyrotechnic system. The components of the system and their binary and ternary combinations have been studied using a stereoscopic microscope, under conditions of controlled heating rate and atmosphere, and the observations recorded using a colour video camera in conjunction with a time-lapse video recorder. Measurements were also made of the intensity of the light reflected from the surface of the sample as a function of temperature. The results are discussed in the light of the studies made by DSC and simultaneous TG-DTA-mass spectrometry.