A woman stands in front of artist Yan Lei's "Color Wheel". Image Credit: Timothy A. Clary/AFP/Getty Images
by Alex Carter
The human eye can distinguish approximately 10 million colors. If you’re anything like us, you’re probably wondering where the other colors are. Is this it? Are we condemned to a life of boring blues and requisite reds? Will we groan at greens and yawn at yellows forever? Apparently not: turns out there are six colors that you can see that don’t exist.
Firstly, let’s get it out of the way … technically, magenta doesn’t exist. There’s no wavelength of light that corresponds to that particular color; it’s simply a construct of our brain of a color that is a combination of blue and red. But it gets stranger. We're not just talking about that sort of thing—we're talking about actual colors that you need to trick your brain into recalibrating itself in order to see.
Our eyes have receptors called cones for three different colors: red, green, and blue. By measuring the combined responses, secondary colors can be constructed. For example, a combination of red and green makes yellow.
However, if the eye reports the red and green receptors are being stimulated, the brain also processes the absence of blue. This is not only important for being able to interpret colors instantaneously, it also allows the brain to correct for different color temperatures. Our brains, for example, are likely to report white paper under a blue light as white, despite only triggering the blue receptors. It is this calibration that we can exploit to see colors that don't really exist.
The other component relies on the eye’s persistence of vision. Receptors on the retina do not refresh instantaneously and keep transmitting for a few milliseconds after the stimulus is removed. This is why staring at anything with sharp contrast (such as this black text on a white background) can sometimes leave an imprint on your vision when you look away.
If your retina keeps sending the same signal back to your brain, eventually your brain stops paying attention, and you actually develop a sort of (safe and extremely short-lived) blindness. In real life, this is practically impossible to achieve, as your eyes naturally move quite rapidly anyway.
So by exploiting these facts about how our eyes work, and exposing our eyes to bright primary or secondary colors, we can saturate the corresponding cones and thus block out other signals. Looking then at the opposite color on the color wheel will then produce a color that is oversaturated—this color is technically imaginary. The effect soon fades, however, as the brain readjusts to the normal world.
To achieve this, you just need a large, bright appropriate color—like this one.
The nonexistent colors that you can see, and the colors needed to see them, are as follows:
To see supermagenta, look at green (see above).
To see superblue, look at yellow.
To see supergreen, look at magenta.
To see superred, look at cyan.
To see superyellow, look at blue.
To see supercyan, look at red.
For example, to see superblue, stare at pure yellow for a minute or so, then immediately look at blue. The blue should appear bluer than blue can be, for a few seconds at least. Try it. We promise it won’t break your eyes.