Eclipse of Titan
See how true cyan and green should look!!
This illusion is an update to the award winning, Eclipse of Mars, (which appeared as illusion of the month at Amos Storkey's Illusion page, and ranked top in the optical illusions poll).
The idea is to stare at the white dot in the centre of the red circle for at least a minute (the longer the better - say 2 minutes!). You may blink, but don't move your head, and never take your eyes off the white dot. As you begin staring, you'll begin to already notice a strange glowing effect as if the surface of Titan is melting from the heat. Don't stop now though! Keep staring away, then finally, after a minute.... SLOWLY.... begin to move your head backwards.
Witness the Eclipse of Titan!!
...and then curse our television and monitors for being unable to reproduce this depth of saturation exactly. Also curse your vision which, also, will never otherwise be able to experience the true Cyan quale, due to colour pollution from the other colour cones in our eyes.
The blue gradient bit to the right is not part of the illusion, but just there to show you that the colour you have just witnessed is not anywhere in the colour palette of your PC/monitor.
Out of all the shades a monitor (CRT or LCD) can reproduce, cyan happens to be the worst in terms of sheer colour saturation, with green following close behind. The amount of red pollution is clearly evident if you take the shiny side of a CD, turn the light off to make the room dark, and fill the screen in bright cyan or #00ffff. On the CD, you should see a great deal of red, aswell as the green and blue. This shouldn't be there, since the only light coming from the monitor should be blue and green! If you were to fill the screen with bright green #00ff00, you'll also see some blue pollution and a massive amount of red pollution.