Is Purple Just A Lie We All Agreed On? Science Says It’s an Optical Illusion

Reading Time: 2 minutes

Synopsis

The shocking claim that purple is an optical illusion challenges everything we know about color theory in branding and design.

Key takeaways

• The color purple doesn’t appear on the visible light spectrum.
• Science suggests purple only exists in your brain as an optical illusion.
• Designers may need to rethink how they define and use purple in branding.

The royal hue is just a pigment of our imaginations.

Purple color is often used sparingly in branding and graphic design. Still, its associations with royalty and luxury can make it a powerful force, as we in the the best uses of color in branding.

Think Cadbury, Hallmark, Taco Bell, and Yahoo. Now science wants to tell us that it’s merely an optical illusion? That’s the suggestion behind the argument that purple isn’t real because it doesn’t exist on the visible light spectrum.

But what about aubergines and prince?

Wait, what? What about aubergines? What about Prince? What about the new Microsoft Office icons? Steady yourself because this requires a reappraisal of primary education.

The rainbow song ‘red, and orange, and yellow, and green, and purple, and blue! And indigo, too? – All wrong, apparently (see our piece on color theory).

Why is purple not on the spectrum?

It may all depend on how you define purple, which is a matter of semantics as much as science.

As many Instagram videos shows, rainbows do feature violet at one extreme. Like the other colors in the rainbow, violet has its wavelength (it’s the shortest that we can see).

As a kid, I always considered violet to be a shade of purple, and many people do.

But no, violet is a real spectral color. The color usually referred to as purple is a mix of a range of colors that fall between the spectral hues of red and violet on the CIE Chromaticity Diagram.

Why is purple technically an optical illusion?

While I’m not convinced that this means ‘purple is fake’ or ‘isn’t a color,’ it does mean that it only exists in our minds, as an optical illusion of physics and neuroscience, hence why there’s no ‘P’ in ROYGBIV.

To create purple in art, the RGB model combines red and blue pigments, while the CMYK model for printing combines magenta with cyan or black.

According to Popular Mechanics, it isn’t supposed to be possible to create a color from wavelengths on opposite ends of the spectrum, like violet and red.

As a compromise to allow us to perceive such conflicting visual stimuli, our brains “bend the spectrum into a circle, making the two extremes meet at purple.”

Therefore, purple is real. Now, can we argue about what indigo color is supposed to look like?

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