The 90 micron thick single temperature film may be similar used as the pressure sensitive film. Cut with scissors it is placed between the body to be tested.
Within the temperature sensitive film, microcapsules with colour and developer respond to the heat and discolour the film. The intensity of staining is proportional to the amount of heat flow. The heat flow is dependent on temperature and time. The requirement is, that the film is pressed evenly. This can be easily checked by using the pressure measuring film Prescale before the measurement.