Just because it's black in the darkI absolutely love the song in question. To be honest, I love pretty much everything by Laleh.
Doesn't mean there's no color
However, we have to talk about those two lines of the chorus.
Color is what happens when light of a certain wavelength within the visual spectrum interacts with the eyes, or whatever similar organ, of a living being. Objects reflect only parts of the visual spectrum due to their physical qualities (which I do not pretend to understand in detail), and that is why we get objects of different colors.
Color is not an intrinsic property of objects, but the result of those objects reflecting light. If you direct a source of red light on a green object, then (if I'm not completely mistaken), the green object will absorb, i.e. not reflect that light, and it will appear gray or even black.
So, in the dark there is indeed no color. It is black exactly because of that fact.
With a more subjectivist philosophy in mind, one could even argue that color only happens when said light interacts with a light-perceiving organ, i.e. an eye which is connected to a working, living brain. Without light to shine on them and an eye to percceive them, the physical properties of the object are still there, of course, but nobody cares. They are, one might quip, potential colors, not actual ones.
So, after all, colors appear to be there before they are hit by lightwaves, waiting to be perceived, like buds that have not opened yet. Just like the acorn is, in a way, a tree in waiting, so is unperceived color a sense perception that just has not had the chance to happen as of yet. The green object hit by red light would, then, be a sadly missed opportunity.
Simply because I'm such a literature buff (and because, by pure chance, I am just at the right time, namely right now, re-reading James Joyce's Ulysses), I shall have to quote the opening lines of the Proteus episode to you:
Ineluctable modality of the visible: at least that if no more, thought through my eyes. Signatures of all things I am here to read, seaspawn and seawrack, the nearing tide, that rusty boot. Snotgreen, bluesilver, rust: coloured signs. Limits of the diaphane. But he adds: in bodies. Then he was aware of them bodies before of them coloured. How? By knocking his sconce against them, sure.