Colour gamut refers to the range of colours that can be reproduced by an imaging system. The definition of gamut is quite clear for displays and for hard-copy printing. Colour image science experts disagree, however, on the definition – or even applicability of the concept – of gamut for cameras. I disagree that there is any meaningful concept of “capture gamut.” In this note, I review trichromacy and metamerism and discuss various gamuts. I conclude that although metamerism is a phenomenon of what I call “31-space,” gamut lives in 3-space. With suitable colour signal processing, a 3-channel camera is capable of acquiring wide gamut images.