Wait… The Colors of the Rainbow Are Wrong?
We’ve all been taught the same thing: red, orange, yellow, green, blue, indigo, and violet—ROYGBIV.
It’s a fundamental part of how we learn colors as children.
But here’s the kicker: that isn’t actually how rainbows work.
For centuries, people have memorized this sequence as if it were an absolute truth, but scientists now suggest that it’s more of a historical artifact than a scientific fact.
Some of those colors shouldn’t even be on the list, while others—like cyan—are mysteriously missing.
If you’ve ever looked closely at a rainbow and thought, Wait, where exactly is indigo? or Isn’t there a really strong blue-green color that no one talks about?, you’re not alone.
The way we’ve been taught to see the rainbow is based on outdated science, and the real story is even more fascinating.
A Colorful Misinterpretation
The reason we think of rainbows as having exactly seven colors can be traced back to Isaac Newton in the 1660s.
When Newton first observed light being split by a prism, he labeled the colors red, orange, yellow, green, blue, indigo, and violet.
But here’s where things get weird:
- The “blue” Newton described was actually closer to what we now call cyan—a blue-green color.
- The “violet” he mentioned was really a deep blue.
- Indigo was likely included to match the seven-note musical scale rather than because it was scientifically distinct.
In reality, when light is separated into its visible spectrum by a prism or raindrops, it doesn’t have clearly defined color bands—it’s a continuous gradient.
This means that colors blend smoothly into one another, making strict divisions like “indigo” and “violet” somewhat arbitrary.
But Wait—Where’s Purple?
Now here’s where things get really interesting.
Purple is nowhere to be found in a rainbow.
That might sound strange, considering that we often see pinks and purples in sky rainbows.
But those colors aren’t actually part of the natural spectrum of light.
Why?
Because a rainbow created by a prism—or by raindrops—only contains colors that exist as individual wavelengths of light. Purple (or magenta) doesn’t have its own wavelength; it only exists as a mix of red and blue light.
So how do some rainbows seem to contain pinks and purples?
It’s all an optical illusion.
According to Henry Reich of MinutePhysics, this happens because:
- Deep blues can appear purplish when surrounded by lighter colors. Our brains interpret small amounts of deep blue as purple under certain lighting conditions.
- A phenomenon called “supernumerary rings” can create extra color bands. These are formed by interference patterns when light waves interact inside raindrops, producing additional rings of unexpected colors—sometimes including pinks and purples.
The Real Colors of the Rainbow
So if Newton got it wrong, what should we say the colors of a rainbow are?
A more accurate way to describe a rainbow’s color sequence would be:
- Red
- Orange
- Yellow
- Green
- Cyan (blue-green)
- Blue
That’s it. No indigo. No violet. No purple.
If that seems strange, remember: color is as much about perception as it is about physics.
Our brains fill in gaps, and cultural traditions (like Newton’s seven-color system) shape the way we describe what we see.
The Science of Supernumerary Rings
If a rainbow is just light being refracted by water droplets, why does it sometimes show extra colors beyond the basic spectrum?
The answer lies in something called supernumerary rings—a lesser-known optical effect that creates additional, thinner bands of color just inside the main rainbow.
- These rings occur when light waves overlap and interfere with each other inside raindrops.
- Unlike the main rainbow, which is formed by single-wavelength colors, supernumerary rings are created by wave interactions, which sometimes produce unexpected colors—including shades of pink and purple.
This means that when you see a sky rainbow with hints of pink or violet, it’s often because of wave interference, not actual purple light being separated out like the other colors.
What This Means for How We See the World
The idea that “ROYGBIV” is an outdated, misleading way to describe the rainbow might seem like a small thing, but it actually highlights a much bigger truth about how we perceive the world.
- Our understanding of color is shaped by history, culture, and even music theory. Newton didn’t have a scientific reason for choosing exactly seven colors—he likely did it to match the seven musical notes of a major scale.
- Our eyes and brains play tricks on us. We see colors that aren’t physically present because of how our vision processes contrast, light, and blending.
- Science evolves. Just because something has been taught for hundreds of years doesn’t mean it’s set in stone. We now know much more about light, optics, and color perception than Newton did.
Forget ROYGBIV, Embrace the Real Rainbow
The next time you see a rainbow, take a closer look. Instead of trying to find indigo or violet, notice the strong cyan band that no one talks about.
Pay attention to how the colors blend smoothly rather than forming rigid stripes.
And if you spot pink or purple, know that you’re witnessing a fascinating trick of light and physics, not an actual spectral color.
It’s time to update our mental image of the rainbow and recognize that nature doesn’t conform to our human-made categories.
The real beauty of a rainbow isn’t in neatly labeled color bands—it’s in the way light and water interact to create something fluid, dynamic, and endlessly fascinating.
And that’s a far better way to appreciate the science of light.
