Octane Blackbody Emission

Last modified: 17 December 2024

The Black Body emission node uses Temperature (expressed via the Kelvin scale) and Power to control the color and intensity of the light, respectively.

Lighting-colour-temperature.jpg

All objects radiate energy warmer than 0 Kelvin, but this energy is not visible to human vision. The average body temperature for a human, expressed in Kelvin, is 310.15 K — too low for our eyes to register as a source of illumination (as this value is actually in the infrared spectrum), though we do perceive the warmth we generate.

The lowest end of the visible spectrum is right around 800 K (embers). A match flame is 1800 K and a standard "Edison" incandescent light bulb is 2800 K. The spectrum below shows color temperature in Kelvin for varying light sources.

colour-temperature-kelvin-scale.png

In other words, when temperature increases beyond a certain point, visible light is emitted, starting with warmer reddish values all the way through cooler blue values.