chromatic vs chromaticity

chromatic is not a noun while chromaticity is a noun.

Word	Noun	Adjective	Verb	Adverb
chromatic	No	Yes	No	No
chromaticity	Yes	No	No	No

chromatic (noun)	chromaticity (noun)
	the quality of a color as determined by its dominant wavelength

chromatic (adjective)	chromaticity (adjective)
being or having or characterized by hue
based on a scale consisting of 12 semitones
able to refract light without spectral color separation