Absorbance vs. Transmittance

Absorbancenoun

(physics) A logarithmic measure of the amount of light that is absorbed when passing through a substance; the capacity of a substance to absorb light of a given wavelength; optical density.

Absorbance

Absorbance is commonly defined as . Alternatively, for samples which scatter light, absorbance may be defined as .

Transmittancenoun

a transmission

Transmittancenoun

(physics) the fraction of incident light, or other radiation, that passes through a substance

Transmittancenoun

Transmission.

Transmittancenoun

the fraction of radiant energy that passes through a substance

Transmittance

Transmittance of the surface of a material is its effectiveness in transmitting radiant energy. It is the fraction of incident electromagnetic power that is transmitted through a sample, in contrast to the transmission coefficient, which is the ratio of the transmitted to incident electric field.Internal transmittance refers to energy loss by absorption, whereas (total) transmittance is that due to absorption, scattering, reflection, etc.