Inspection with thermography is a non-invasive, non-destructive process used in Power Systems facilities. Most temperature signatures that are not in the visible light range can be measured using thermal cameras, thus enabling the search of thermal behavior of porcelain insulators. Overheating can help to detect problems, concerning the proper operation of insulators. The precision of temperature measurement using an infrared camera is influenced by the value of emissivity parameter that is set on camera. In the present study the influence of distance and angle between the camera and the insulator on emissivity parameter value selection in camera is examined experimentally.