The impact of thermal radiation and its associated radiance temperature on nearly all facets of technology and society is tremendous. Reliable temperature measurements are in that context of vital importance in many areas in science, technology, industry and environmental protection. This implies the use of a sound traceability framework, involving accurate reference standards to begin with and a calibration procedure for radiation thermometers that incorporates all sources of measurement errors (uncertainties). Latter procedure should be two-fold; first a traceable comparison is made against a blackbody radiator, then the instrument is evaluated and/or calibrated in its application. In this paper all three traceability steps will be addressed, that is, the dissemination of the international temperature scale of 1990 (ITS-90) and the initial and on-site calibration of radiation thermometers. First two steps were investigated in detail and improved on European level in the TRIRAT program that was funded by the European Community. This included international intercomparisons for radiation thermometer calibrations and recommendations for the standardization and testing of infrared radiation thermometers as transfer standards. An other project, ILART, bridges the gap in traceability between initial calibrated radiation thermometers and their industrial application. It involves realization of a portable calibration facility, intrinsically insensitive for surface emissivity and reflection error using active two-color thermometry.