Are colors subjective or objective or both?
A deep rich complicated question! A short (too short) answer would go with both, depending what you mean by 'color.' There are subjective aspects to color (perceived color), and there are objective aspects (physical properties, light properties, etc.). The big question of course is just how these two aspects are related. Are they independent in some sense, or intimately related, and if so how? Can perceived color, the perception of color, be identified with or reduced to objective properties, and if so which? There is a ton of literature on this, but you might start with the classic Larry Hardin's "Color for Philosophers."
hope that's useful -- to start