Definitions for "Emittance"
The emissivity of a material, expressed as a fraction. Emittance values range from 0.05 for brightly polished metals to 0.96 for flat black paint.
The ability of a material to emit radiant energy from its surface. Also called emissivity.
ratio of radiation emitted by a body to the emission of a full radiator (blackbody) at the same temperature (a.k.a. emissivity) [--]   Emissionsgrad