blankness vs emptiness

blankness and emptiness both are nouns.

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

As nouns, emptiness is a hypernym of blankness; that is, emptiness is a word with a broader meaning than blankness:

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