black as the ace of spades vs sombre

black as the ace of spades

• Utterly black; pitch-black. 

sombre

• Dull or dark in colour or brightness. 

• Dark; gloomy; shadowy, dimly lit. 

• Melancholic, gloomy, dreary, dismal; grim. 

• Grave; extremely serious. 

• To make sombre or dark; to make shady.