Why Do You See 7 Colors in The Rainbow?

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Seven colors are in the rainbow. That is what people have been taught, seen, and perceived from a young age. Red, yellow, green, orange, indigo, blue, and violet, those colors also appear as an acronym of ROY G.BIV. But are they the real colors in the rainbow? Is it tell and make up the rainbow as it is now? And why seven? 

While the conception of the rainbow colors has been there for a long time ago, many are still curious about the origin. Why can you see 7 colors in the unique natural arching light reflection? To help you understand how such a beautiful natural occurrence appears in seven colors, here is some information to digest. 

The Confusions

Yes, the concept of seven hues in the rainbow is pretty customary in life. But, the idea is a little bit confusing to digest. Why so? You need to remember that many designers or even people will say that there are only three primary colors. They are blue, yellow, and red. But upon mix and match, the combination will make new three secondary hues. 

The secondary hues are purple, green, and orange. Sometimes, people also include the white and black paint as part of the natural hues. If you put the primary and the secondary together, it only makes up to six basic colors. So, where is the one? Where does the indigo appear? And how do people make it as part of the rainbow? 

There is an explanation that shows purple in the rainbow is a hue that is subdivided into the mix of more blue-ish hue and purple together. Yes, it makes the concept of the color getting weirder. And surprisingly, that idea of a unique tint sequence came from Isaac Newton, who invented the gravity theory. His idea was also followed by ancient Greek philosophy.   

The One That Discover Rainbow 

As said before, the natural rainbow occurrence is not a human-made invention. It is just that one genius mathematician can describe the colors in the rainbow and make it one of the huge inventions. The first name behind it is Aristotle, the Greek Philosopher that fused about the rainbow back in around 350 BC. 

His idea was later continued by the Roman philosopher years after him in 65 AD. The Roman philosopher is Seneca, who is the one that predicted the discovery of the prism effect. After that, the natural phenomenon has been one of the favorite subjects for naturalists and philosophers to examine. From then, they found that the rainbow not only appears in the sky but also in other circumstances.   

One of the huge discoveries is that the rainbow effect can appear due to the droplet of water vapor and sunlight. Centuries later, the brilliant gravity father, Issacs Newton, found more ideas from the rainbow. He can prove that the white light is made of many colors after getting it split using a prism. 

Along with the previous invention and works of others before his, finally, there is an explanation of how the rainbow forms and what it looks like. One notable thing is the sequence of colors in the phenomenon. The ROYGBIV or red, orange, yellow, green, blue, indigo, and violet hues will never change and come in the same order.  

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The Colors Of Rainbow

So, is it seven colors in the rainbow? The idea still lasts to this day. However, there is much research and closer inspection that show that there are more than just seven. It tells that the seven colors are just the simplified version of the myriad of individual spectral colors in it. The phenomena have mixed and overlapped so many hues that only seven can be captured by human eyes. 

The metoffice.gov.uk explains that the basic sequence of the rainbow's colors consists of from 380 nm to 780 nm wavelength. In other words, the tints span from the shortest Violet to the highest Red. Among those spans, there is a whole range of colors that humans cannot distinguish with naked eyes. So, the seven colors ideas stay intact as the best recognition. 

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The Visual Spectrum

As said in the previous point, there are some shades hardly visible in the human eye. This kind of concept is in the same way as how the visual spectrum is. The truth is that humans see color in the form of light waves. It is an idea that not many people understand. So, they only use the subtractive method such as primary or red, blue, and yellow. 

So, subtractive color mixing is the most easier to follow. Many people relate the ideas with paint mixing, which uses primary hues to make different shades. As an example, the mix of yellow and red will appear as green. The visualization has been around and used, including to explain colors in the rainbow. 

However, what happens in the rainbow sequence is more than just the subtractive mixing. The best way to explain the rainbow colors comes from the additive color mixing method, which focuses on the light waves. In this case, the rainbow color is determined by three different primary colors, which are red, blue, and green. The two mixes have unique results. 

Sir Isaac Newton figured out that when using a prism to break the white light, there will be a lot of visual spectrum of the colored light. In this case, people call it a rainbow. But, upon inspection, the white light separation comes in ranges of nanometers which later explains how some colors are invisible for human eyes. 

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Color As A Concept 

This is where the physical concept of colors comes in the shape of photons or light quantum by Einstein. The fundamentals of photon theories apply to explain how it transfers energy in the quantized formula. So, you got the E=h*n where the N is the photon frequency, and his the Planck constant. 

To make it simpler, you can refer to the colors in the rainbow based on the electromagnetic spectrum. The photons come in different ranges starting from high energy known as gamma rays and the lower one as radio waves. The photon can be considered as the speed of light c, and the cycle will be known as the photon wavelength I. 

So, what is the relation between colors or the hues that you can see in the rainbow? The relation comes from how the I=c/n is also known as frequency. The light that can be perceived by humans also has a specific wavelength frequency. It later shows why some colors are easier to describe, or some are simply unseen. 

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The Perception Of Colors By Humans 

In this case, human sensitivity to the wavelength frequency is limited from 700 nm to 400 nm. As said in some previous points, the seven colors you can see from the rainbow are the sequence that helps categorize and explain to human eyes. But, if you take the hue ranges based on the wavelength, the rainbow will have more color that is simply unexplainable. 

That visual spectrum of colored light was where you find the name of UV or ultraviolet and infrared or IR. Inside the 400 nanometers to the 700 nanometers wavelength, you got seven different zones. It is where the ancient people explained the sequence of the rainbows. It starts from violet in 400 nanometers and ends with deep red in 700 nanometers. 

How about the below or the above range? In the case of colors in the rainbow sequence, it is pretty much invisible for human eyes. Below 400 nanometers, you will find Ultraviolet which is the sunlight that hardly has any colors. In the 700+ nm is infrared, which is also known for its damaging properties. 

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In those wavelengths, you will find that every nanometers hue will bleed into the other. The violet will bleed and blend with the dark blues. After that, you can see light blues, green, yellow, orange, and red. These bleeds are harder to define, which is why it is called a spectrum. It also has a pretty random distinct set of tint, which is hard to capture and explain. 

So, how can the human eye capture that sequence of hues? With the help of nature, humans do not need an antenna to capture some tints. While indeed the appearance is limited, still the human eye can capture hues as a vision. In this case, the human eye itself also has photoreceptors or proteins that help capture the wavelength. 

The retina' photoreceptor cell or cones will help configure the wavelength and give the sequence of colors in the rainbow. With that retinal cell doing the job, the stimulus of a certain wavelength creates three parameters to indicate hues. They are called L, M, and S that are the response of the types of the photoreceptor to the stimulus.  

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The Magic Of Pythagoras And Newton Pattern From Ancient Greece  

As you know the wavelength, you might think, why seven? Why can't the ancient Greece philosopher or mathematician shows that it has plentiful hues that humans cannot capture? Surprisingly, the seven tints are the way to explain. That is why it is what people can see and describe what the rainbow is. 

But if you are going to talk further on why and how, you can go back to the 6th century BC. The well-known mathematician Pythagoras tried to take real-world phenomena and associate them with numbers. It includes the beautiful rainbow as his subject. And surprisingly, his research always comes out with seven. 

Starting from his effort to break down musical notes to mathematical equations that resulted in seven notes. There is also the weirdly unique research where the theory of heavenly bodies will move according to mathematical patterns. It again shows seven as a time sequence. It also applies to the colors in the rainbow phenomena.

As dumb as it sounds, many points in this life have seven as the lucky number. The ideas of the rainbow hues, the liberal arts subject, days of the week, seven dwarves, or the seven deadly sins, have seven in it. But, then how come the unique ideas apply in the rainbow, which is a natural phenomenon and has a complicated wavelength context?

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With his work known as the basics of heliocentric or planetary motion and theory of gravity, his idea of seven hues is uniquely believable. He corrected his finding of five colors spectrums consisting of purple, blue, green, yellow, and red to seven colors spectrum. He added orange and indigo, which ho have a huge connection with music and colors. 

From that information and ideas come the seven colors in the rainbow theory from centuries ago. But, the idea is not too far from the wavelength ideas and how Isaac Newton described seven hues as the best categorization. And those are where the theory and perception of the rainbow come from. Most of them come from the old Greece findings. 

Another Intake Of Retinal Cells And Wavelength 

If you are not satisfied with the idea of lucky seven, you might have to dig deeper into the   . There are photoreceptor proteins in humans' eyes or retinas. Each cone of the photoreceptor cell in your cell membrane can absorb photons to capture the hues and perceive them. 

In this case, the protein that captures the photon or the spectrums will channel to the cell membrane and change shapes. That is where the flow of ions happens. With all of the complex biochemical processes, the nerve impulse flow will reach and preprocess several layers of neurons in the retina. The process is very complex since it processes color in ways so humans can see it. 

When the nerve impulse reaches the visual cortex and optic nerve, the spectrum hues information on the rainbow will be processed. It is where the retinal cells will convert the stimulus into L, M, and S wavelengths. When human eyes are in the normal condition, the response will have a specific wavelength perception. Thus, the implication will show colors. 

That measurement system that relates to L, M, and S wavelength explains seven different zones in the color spectrum. It can be one of the reasons why humans perceive that the colors in the rainbow consist of seven hues. But does that mean everyone sees the same thing? One thing that you need to consider is that humans and other species will have different types of photoreceptors. 

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If humans can capture seven hues, it will be different for birds that mainly have the fourth photoreceptor. Since the bird has more, they can see a greater number of hues in the rainbow. Supposedly, the bird's mind shows that the fourth photoreceptor in its retina allows them to capture nine regions in the light wavelength. 

So, the best hypothetical of bird vision is that they can perceive more colors. The simple combinatorial will be the factor of defining several hues that appear in the eyes. In other words, the more photoreceptors, the more hues from the rainbow will be visible. The idea of a photoreceptor also helps define the chance of synthesizing color by mixing. 

The subtractive or pigmentary mix using three primary shades for printers or oil paints is now easier to explain. The cyan, yellow, and magenta are what you can find upon mixing some photons. Magenta is the non-existence hues without the mixture of red and blue photons. 

You can also use the same example of the other nonvisible hues in rainbows, such as white color. It has no individual photos that trigger stimulus in your retina. But, the white itself is in the visible band by mixing green, blue, and red photons (additive colors mixing). So, the perception of colors of mixing, wavelength, and retinal ability is the answer. 

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Final Words

From that human eyes' abilities, the primary ideas or conclusion popped out to explain the seven colors in the rainbow. It also answers some theories of different tint or shades interpretation through different species. In other words, dissimilar eye conditions will show diverse hues captured by the individuals. 

The number and the complex process of wavelength procession also explain the two different color mixing theories. The additive and the subtractive mixing will have different results since the primary spectrums are not the same. It also tells the aspect of non-physical colors. The best example is the magenta and white that are hardly visible to human eyes. 

So, the reasons for the seven-hues rainbow sequence come from the wavelength and the human's ability to capture it. Human eyes can capture color wavelengths from 400nm to 700nm, but most bleed and blends are hardly visible. That is why sir Isaac Newton uses prism and categories seven hues to simplify in explaining rainbow's colors.