emptiness vs blankness

emptiness and blankness both are nouns.

Word	Noun	Adjective	Verb	Adverb
emptiness	Yes	No	No	No
blankness	Yes	No	No	No

As nouns, blankness is a hyponym of emptiness; that is, blankness is a word with a more specific, narrower meaning than emptiness:

Other hyponyms of emptiness include hollowness, vacancy, vacuity, vacuum.

emptiness (noun)	blankness (noun)
the quality of being valueless or futile	the state of being blank; void; emptiness
an empty area or space
the state of containing nothing
having an empty stomach