Colour conversion apparatus comprises mapping circuitry configured to map pixels of an input image having colour components in an input colour space to pixels of an mapped image having colour components in an output colour space, the input colour space and the output colour space being different colour spaces such that at least a subset of colours representable in the input colour space are not representable in the output colour space; the mapping circuitry being configured to: convert pixels from the input colour space to an intermediate colour space in which a colour space representation of hue approximates to a consistent perceived hue independent of brightness and/or saturation; map pixels in the intermediate colour space which lie outside a region of the intermediate colour space corresponding to representable colours in the output colour space to generate mapped pixels so that the mapped pixels lie within that region, by varying the brightness and/or saturation of those pixels in the intermediate colour space but leaving the hue of those pixels substantially unchanged; and convert the mapped pixels from the intermediate colour space to the output colour space.