optris LS – E2006-01-A 
40 
 
►  Cove a part of the surface of the measuring object with black, flat paint with an emissivity of 0,98. Adjust the 
emissivity of your infrared thermometer to 0,98 and take the temperature of the colored surface. Afterwards, 
determine the temperature of a directly adjacent area and modify the emissivity until the measured value 
corresponds to the temperature of the colored surface. 
 
Characteristic Emissivities 
 
In case none of the methods mentioned above help to determine the emissivity you may use the emissivity 
tables (Appendix A and B). These are average values, only. The actual emissivity of a material depends on the 
following factors: 
  temperature 
  measuring angle 
  geometry of the surface 
  thickness of the material 
  constitution of the surface (polished, oxidized, rough, sandblast) 
  spectral range of the measurement 
  transmissivity (e.g. with thin films)