What is a likely reason for a shade of orange becoming too black and lifeless?

Correct answer: Excessive use of black paint

The governing concept is shade formation and control of value. Orange becomes a shade when black is added, but excessive black lowers the value too sharply and suppresses the colour’s brightness and warmth. The result can look muddy, nearly black, and lifeless. A little yellow may shift orange toward yellow, while a balanced red-yellow mixture creates orange and a clean palette prevents contamination rather than causing dullness.