redness vs chromatic colour

redness and chromatic colour both are nouns.

Word	Noun	Adjective	Verb	Adverb
redness	Yes	No	No	No
chromatic colour	Yes	No	No	No

As nouns, chromatic colour is a hypernym of redness; that is, chromatic colour is a word with a broader meaning than redness:

redness: red color or pigment; the chromatic color resembling the hue of blood
chromatic colour: a color that has hue

Other hypernyms of redness include chromatic color, spectral color, spectral colour.

redness (noun)	chromatic colour (noun)
red color or pigment; the chromatic color resembling the hue of blood	a color that has hue
a response of body tissues to injury or irritation; characterized by pain and swelling and redness and heat