My daughter loves unicorns and rainbows. Because of this, I absolutely have to remember what colors the rainbow is and how they go together. Red, orange, yellow, green, blue and purple. Nothing heavy. Anyone can do that. But scientists have figured out that purple is not in the rainbow. I mean, they say that this color is not at all. Nonsense, right? We can see it. We all know it. But according to the experts, it’s just something we create in our heads.

Purple is not purple.

In fact, they say the color purple has something that violet doesn’t. It has its own wavelength of light. Surely you know that purple wavelengths are real. Ultraviolet radiation is the reason we get slathered in sunshine. So what about the purple one? The real colors are said to be red, orange, yellow, green, blue and indigo.

Purple is supposedly our brain’s way of resolving conflict. Red and blue (or purple) are on the opposite side of the spectrum. When both of these wavelengths hit the same place, the eyes and brain don’t know how to deal with them. Or actually, they do. Our brains and eyes work together to create a color we call magenta. But it doesn’t really exist as a separate wavelength.

━━ ( Source: David Brooke Martin /  Unsplash+ )

Light spectrum

The visible light spectrum detected by the human eye is only a small fraction of the wavelengths. These colours are made available to us by the millions of densely arranged photoreceptor cells known as cones that respond to the light that hits our retina. We only see colours at wavelengths from about 350 to 750 nanometres. This is why the human eye does not distinguish between UV and infrared light.

If this needs to be explained in detail, it is quite simple. Ultraviolet wavelengths are too short for our photoreceptor cells. In contrast, infrared wavelengths are too long for the human eye. It’s worth adding that cones themselves cannot see colours, but they send out electrical signals based on wavelengths. These are absorbed via the optic nerve to the back of the brain where they are analysed and sent to the visual cortex. The brain then determines what colour you’re looking at. Long process, isn’t it?

So what about the existence of colour?

From what we’ve found, it looks like magenta doesn’t actually exist. Does it? The executive director and principal investigator of the Wharton Neuroscience Initiative at the University of Pennsylvania says there is, in fact , no color. “It’s all a process of our nervous system, and therein lies the beauty and complexity of the whole process.” However, purple is thus known as a non-spectral color.

The reason is that it doesn’t actually exist as actual electromagnetic radiation. Magenta consists of two wavelengths of light. Spectral colors. That is, red, yellow, green, blue and indigo consist of only one wavelength. So physically, the color magenta doesn’t really exist. But it has fascinated people for millennia.