redness vs spectral color

redness and spectral color both are nouns.

Word	Noun	Adjective	Verb	Adverb
redness	Yes	No	No	No
spectral color	Yes	No	No	No

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

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

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

redness (noun)	spectral color (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