The classification of qubit channels is known since 2002. However, that of rebit channels has never been studies so far, probably due to the scarcity of concrete rebit examples. In this paper we fill the two gaps by exhibiting both the complete rebit channel classification and also by discussing its relevancy in a recent colour perception theory based on quantum information. In particular, we show that rebit channels can be used to determine the individual chromatic state space of human observers, including those with colour deficiencies. Moreover, we propose a qualitative explanation for the perceptual phenomenon of visual adaptation to a non-neutral illuminant.