optical density
Noun
Meaning
(physics) a measure of the extent to which a substance transmits light or other electromagnetic radiation
Source: WordNetSynonyms
Hypernyms
Examples
Differences in optical density will show up as differences in relief.
In the USA honey is also graded on its color and optical density by USDA standards, graded on the Pfund scale, which ranges from 0 for "water white" honey to more than 114 for "dark amber" honey.