Follow Us: Twitter LinkedIn Facebook


Specialty Graphic Imaging Association


As defined in the SGIA Glossary for the specialty imaging community.

An index of the light absorbed by a medium compared to the light transmitted through it; numerically, it is the logarithm of the ratio of incident spectral irradiance to the transmitted spectral irradiance, a unit-less number. (Absorbance implies monochromatic radiation, although it is sometimes used as an average applied over a specified wavelength range).