Snowden, Thompson and Troscianko: Basic Vision (revised edition)
Colour vision tests
A run through some of the Ishihara plates that are used to test for colour blindness. Note that the nature of the monitor you are using alters the colours slightly, so this should not be used as a diagnosis. However, if you do appear to have problems it would be worth having this checked out by a professional.
Just the colour aftereffect again. However, the effect is amazing. The inducing image is barely recognisable in its “reverse-colour” form but then produces almost perfect colour when the black and white image is displayed for a couple of seconds (indeed, many people do not realise they are looking at a black and white image!). The impression of colour information also helps here as it happy to follow the contours produced by the black and white image giving the impression of precise colour boundaries.
For a slightly more “racey” image of the same effect try: