M310-HT Manual
Appendix A: Calibration & Emissivity
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Background Influence On Apparent Emissivity
When using a blackbody source at temperatures well above ambient, common sense dictates
how the blackbody will behave. When using a source close to ambient temperatures, different
things happen. Since the background such as the room, wall, and you could be warmer than the
blackbody emitter, the energy emitted from the emitter is the sum of the background reflection
and the emitter temperature. When emitter emissivity is less than 1.0, the background energy
times (1-emissivity) reflects to the device under calibration. For this reason, the M310-HT may
appear to have a higher “apparent emissivity” near ambient than when operated at higher
temperatures.
