Blackbody models are used as referential temperature measuring gauges for radiation
thermometers calibration. Their emissivity is usually determined by calculation. The
presented paper describes an experimental device used to measure local effective
emissivities, using an optical radiometer. The methods to measure and evaluate emissivity
and temperature are described. The results are compared with the theoretical model of a
cylindrical-conical cavity used to calibrate radiation thermometers.