Learning Resources for Year 8 (Provided by Roche Court Educational Trust).
Complementary colours and how your eyes can play tricks with them
Stare at the centre of the coloured circle for as long as you can. You will notice an aura of light begin to play around the edge and it may even appear to glow.
Move to the blank image (white square) while still staring in exactly the same spot in the centre of the screen. You should see the complementary colour in a purely light based form that is being generated by your eyes.
As the colours on screen are being formed by RGB light from the monitor, you will not see pure pigment complementary colours. You may even see more Cyan, Magenta variations.