In this article, we explore Wittgenstein's theory of the logical form of our concepts and statements of colour, starting with his solution to the so-called "colour exclusion problem" by reference to the notions of "system of propositions " and "scale", but extending it to account for similar phenomena that have sometimes been considered empirical, but Wittgenstein takes to be logical, such as the comparison among colours in terms of lightness, saturation or hue, the questions of which colours are primary, and whether it is possible to perceive a colour no one else has ever perceived. Furthermore, we will try to show how Wittgenstein's remarks on colour are best understood as illustrating general philosophical ideas on logical structure that have deep repercussions beyond the limited domain of colour.