Magenta doesn't exist as a real color—it's a hallucination created by your brain when it encounters a combination of light wavelengths that shouldn't produce any color at all. Unlike every other color you see, magenta has no corresponding wavelength of light.
Real colors exist on the electromagnetic spectrum: red has a wavelength around 700 nanometers, blue around 450 nanometers, and green around 550 nanometers. But magenta appears when your eyes detect both red and blue light simultaneously with no green light present. Your brain literally invents magenta to fill a gap in visual processing.
This happens because your eyes have only three types of color receptors (red, green, and blue), but the visible spectrum is continuous. When red and blue receptors fire together without green activation, your brain creates magenta as a "placeholder" color to represent this impossible combination.
Artists have exploited this optical illusion for centuries. Magenta pigments aren't actually magenta—they're materials that absorb green light while reflecting red and blue light. The "magenta" you see is your brain's interpretation, not a real property of the object.
Other impossible colors exist too: stygian blue (darker than black), self-luminous red (brighter than white), and hyperbolic orange (more saturated than possible). These colors can only be seen under special laboratory conditions, proving that human color vision is far stranger than we realize.