This is a relevant article on the BBC about our perception of colour. There was also an episode last night on BBC 2 about it, but I missed it. You can watch it here on iPlayer though. Although it’s quite obvious that each of us will see colours differently as a result of many colluding factors including the distribution of cone photoreceptors on our retina plus signal processing in the visual cortex, it’s worth considering that combined with different monitors, printers and related colour profiles that we have yet another layer of complexity in dealing with colour and how we present it to users. There is also a slightly more technical piece about perception of colour when multiple wavelengths are present here.