monochrome vs black and white

monochrome and black and white both are nouns.

Word	Noun	Adjective	Verb	Adverb
monochrome	Yes	Yes	No	No
black and white	Yes	Yes	No	No

As nouns, monochrome and black and white are synonyms defined as:

monochrome (noun)	black and white (noun)
a black-and-white photograph or slide	a black-and-white photograph or slide
painting done in a range of tones of a single color	communication by means of written symbols (either printed or handwritten)

monochrome (adjective)	black and white (adjective)
having or appearing to have only one color	not having or not capable of producing colors