pitch blackness vs darkness

pitch blackness and darkness both are nouns.

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

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

Other hypernyms of pitch blackness include dark.

pitch blackness (noun)	darkness (noun)
total absence of light	a swarthy complexion
	having a dark or somber color
	an unenlightened state
	an unilluminated area
	absence of light or illumination
	absence of moral or spiritual values