lightlessness vs blackness

lightlessness and blackness both are nouns.

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

As nouns, lightlessness and blackness are synonyms defined as:

Other synonyms of lightlessness include black, pitch blackness, total darkness.

lightlessness (noun)	blackness (noun)
total absence of light	the quality or state of the achromatic color of least lightness (bearing the least resemblance to white)
	total absence of light