'Colour' is a word with two quite different meanings. This was recognised in the sixteenth century by people like Montaigne and almost certainly for centuries before.
One meaning of colour is an experience we have on looking at things. It arises in the brain. Newton called it a 'phantasm in the mind'.

The other meaning of colour is a collection of different dynamic properties in the outside world that have in common the tendency to give as the experience in the first meaning. These include preferential reflectance of a particular wavelength (red tomato), preferential emission of a wavelength (red hot coal), preferential transmission of a wavelength (red wine) and the tendency to preferentially depolarise red-sensitive cones (red light). These dispositions have nothing in common but all get called red vicariously.

So there is no either/or right answer. Colour in one sense is in the head. In the other sense it is outside. Confusing the two leads to endless circular discussion.