amber vs yellowness

amber and yellowness both are nouns.

Word	Noun	Adjective	Verb	Adverb
amber	Yes	Yes	No	No
yellowness	Yes	No	No	No

As nouns, yellowness is a hypernym of amber; that is, yellowness is a word with a broader meaning than amber:

amber: a deep yellow color
yellowness: yellow color or pigment; the chromatic color resembling the hue of sunflowers or ripe lemons

Other hypernyms of amber include yellow.

amber (noun)	yellowness (noun)
a deep yellow color	yellow color or pigment; the chromatic color resembling the hue of sunflowers or ripe lemons
a hard yellowish to brownish translucent fossil resin; used for jewelry

amber (adjective)	yellowness (adjective)
of a medium to dark brownish yellow color