Extended Area Black Body

Blackbody is an idealized body that absorbs all incident electromagnetic radiation, The name “black body” is given because it absorbs radiation in all frequencies, not because it only absorbs, a black body can emitblackbody radiation.

In this blog post, we are discussing about the Extended area black body and its significance

Before start to describe it let’s talk about some basic things about it.

As we know that a blackbody is a physical material with zero reflectivity and perfect emission. The main applications for these sources are calibration of Non-Contact Temperature sensors such as thermal imagers, Pyrometers.

Types of black body : In the pyrometer calibration industry many types of black body available which are different in size, shape and body structure. Every black body have different dimension and shapes. These are available in the industry in wide range.

Extended area blackbody is one of them in this blackbody.

Extended area black body is defined by the large emitting surface area precise temperature control with good uniformity. Tempsens make Blackbodies are state of the art, highly accurate and stable with different standard sizes and temperature ranges. The LBBCHLBBH & LBBCH Series Extended Area black bodies are low temperature infrared reference sources operating either in absolute or differential mode.

This Black body series featuring the very high stability, they are particularly well adapted for the characterization and performance validation of a very wide range of IR Sensors, such as high resolution cameras for Thermography and long range thermal imagers. Essentially the black body emits a known amount of energy for an infinite number of wavelengths. This enables to draw the expected black body radiation curve for a given temperature. Temperature is accurately controlled by High accurate PID self tuning controller


  • The Black body emitter is made of a metal having excellent thermal conduction, with high emissivity paint.
  • The emissivity of the painted area would appear to a thermometer to be high, even if the original unpainted surface of the target was quite low.
  • The heaters are fixed along with the emitter plate for better thermal contact and uniformity. It also enhances the thermal efficiency, and arranged to improve the temperature distribution at target area.
  • The blackbody temperature is controlled by PID system using SSR.
  • IR sensor is used for calibration of the blackbody

Few points to be consider to choose right Black Body for your application:
1. The type of calibrator you need depends on the type of IR thermometers you will be calibrating.
Some of the factors to consider are:

  • Distance-to-size-of-spot ratio (D:S ratio)
  • Emissivity setting of the IR thermometer
  • Operational spectral band of the IR thermometer
  • Temperature range
    • Your IR thermometer has a temperature range. From below 0 °C to 500 °C you can be served very well by a large area emitter calibrator. Above 500 °C it requires a lot of power to heat the emitter surface, and the temperature losses become very significant.
    • Usually, a cavity-type blackbody is used above 500 °C. This limits the types of thermometers that can be verified above 500 °C by calibration to higher end thermometers with larger D:S ratios.

2. A Large surface IR calibrator typically has an emissivity in the 0.93 to 0.97 range. The emissivity value depends on:

  • What Type of paint we use
  • What Type of metal we use
  • Exposure to time and temperature
  • Quality of the surface (peeling, scratches, films, ice, bumps or ridges)
  • Wavelength


  • Defense
  • Industrial Thermography
  • Thermal Camera Calibration