photographic density vs optical density

photographic density and optical density both are nouns.

Word	Noun	Adjective	Verb	Adverb
photographic density	Yes	No	No	No
optical density	Yes	No	No	No

As nouns, photographic density and optical density are synonyms defined as:

photographic density and optical density: (physics) a measure of the extent to which a substance transmits light or other electromagnetic radiation

Other synonyms of photographic density include absorbance, transmission density.

photographic density (noun)	optical density (noun)
(physics) a measure of the extent to which a substance transmits light or other electromagnetic radiation	(physics) a measure of the extent to which a substance transmits light or other electromagnetic radiation