Venetian red vs sepia

Venetian red and sepia both are nouns.

Word	Noun	Adjective	Verb	Adverb
Venetian red	Yes	No	No	No
sepia	Yes	No	No	No

As nouns, Venetian red and sepia are synonyms defined as:

Other synonyms of Venetian red include burnt sienna, mahogany, reddish brown.

Venetian red (noun)	sepia (noun)
a shade of brown with a tinge of red	a shade of brown with a tinge of red
	rich brown pigment prepared from the ink of cuttlefishes