Of course if there's no light around, there's no colour that you can see. On the other hand, the wall must have some property that makes it be blue. That property is still there in the dark.
— Mike W.
Is Mike referring to the property of excited states, or the property that the states are excitable (via split d-orbitals or conjugated orbitals)?
I understand that anything that we see as coloured but not glowing is transmitting unabsorbed light — the complementary colour of the absorbed light — which is only possible when electrons jumping from ground to excited states.
What I'd like some clarity on is whether those excited electrons fall back to their ground state in the absence of light (another potential reason why colour does not exist in the absence of light). If the electrons do, then I guess the property Mike's referring to is the excitability of the electrons — which makes sense.