Impossible Colors

Magenta isn't alone. Your visual system has other glitches:

• Stygian blue: Stare at bright yellow, then look at black. You briefly see a blue darker than black should allow.
• Self-luminous red: With similar afterimage tricks, you can see a red that seems to glow with no light source.
• Hyperbolic orange: A claimed hue more saturated than any orange that real light can produce.

These "impossible colors" hint that color isn't a property of the world out there. The wavelengths are real, but the color is a perceptual construct — a story your brain tells based on what its cones report.