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How to set the emissivity

  • June 29 2023
  • Riho Kato
放射温度計 AD-5635


Accurate emissivity must be set in order to accurately measure the temperature of the material surface with a radiation thermometer.

For that purpose, it is necessary to obtain the emissivity of the material, and there are three methods.

①Compare with a contact thermometer (see diagram below)

 The object to be measured that has been adjusted to the actual temperature

 Measure at the same time with a calibrated contact thermometer and the radiation thermometer used.

 Adjust the emissivity setting of the radiation thermometer so that the measured value of the radiation thermometer is equal to

 the measured value of the contact thermometer.

How to set emissivity using contact type thermemoeter 3

②Use black body tape or black body paint (spray) (see below)

 Affix a black body tape or adjust the temperature of the measurement object coated with black body paint

 to the temperature for actual measurement,

 Measured with a radiation thermometer set to the emissivity of black body tape or black body paint (around 0.95).

 So that the temperature display value of the part without black body tape and paint is the same as the measured value

 of the part with black body tape and paint

 Adjust the emissivity setting of the radiation thermometer.



Setting emissivity using blackbody tape

③research in the literature

 Investigate the emissivity described in literature and the web.

 However, with this method, the objects to be measured are not covered,

 Please note that the values ​​may vary depending on the surface condition, temperature, etc.

 A list of representative emissivity for each material is posted in the " What is emissivity? "article.


In our company, we offer products with adjustable (changeable) emissivity ranging from 0.10 to 1.00 in increments of 0.01.

These products include AD-5634, AD-5618, AD-5614, AD-5616, AD-5612WP, and AD-5612A.


We also provide a product, AD-5613A, which allows for setting (changing) the emissivity from 0.05 to 1.00 in increments of 0.01.


Additionally, we offer a product, AD-5635, which allows for selecting from emissivity options of 0.95, 0.70, and 0.30.


We also offer infrared thermometers that can be connected to separately sold thermocouple temperature sensors.

By using the method of "comparing with contact-type thermometers," it becomes easy to set the emissivity.