blackness vs darkness

blackness and darkness both are nouns.

Word	Noun	Adjective	Verb	Adverb
blackness	Yes	No	No	No
darkness	Yes	No	No	No

As nouns, darkness is a hypernym of blackness; that is, darkness is a word with a broader meaning than blackness:

Other hypernyms of blackness include dark.

blackness (noun)	darkness (noun)
the quality or state of the achromatic color of least lightness (bearing the least resemblance to white)	a swarthy complexion
total absence of light	having a dark or somber color
	an unenlightened state
	an unilluminated area
	absence of light or illumination
	absence of moral or spiritual values