How Do We See Color? Exploring the Wonders of Human Perception and Vision

Senior couple sitting on wooden pier looking at colorful sunset near the sea with a flying flamingo reflected on the calm water

The world is filled with an undeniable beauty. Almost everyone has had moments in life where they’re stopped short by the sheer breathtaking wonder around them. For some, this might involve a majestic golden sunset. Others might have fond memories of the whites and blues of a distant snow-capped mountain. And, of course, the beautiful contrast of the stars and planets against the blanket of night is always amazing.

All of these events may seem quite distinct from each other. But they have two important things in common. One is that beauty comes about through color. However, there’s one other component to keep in mind. Every moment of breathtaking beauty also occurs through the interaction of the world, our eyes, and our brain. We often forget that the concept of beauty and color is built upon a foundation of human biology and psychology.

So how do we see color, and how exactly do the human eye and brain work together to process it? Let’s find out!

Looking for the Source of Color

A red rose in a dark room where the lights have been dimmed

Think back to the most beautiful landscapes you’ve ever seen. Consider how all the colors worked together to make a truly breathtaking scene. Now consider where that beauty comes from. We naturally start to think about individual flowers, trees, and open skies as a source of beauty. But it’s, in fact, better to begin with our own eyes.

Objects don’t really possess color in the way we assume. Consider a single, beautiful rose. The vibrant red of a rose’s petals has been celebrated in countless songs and poems. What’s more, the green stem of a rose has a rich beauty all its own. But now consider what happens when someone begins to dim the lights. As the light in a room diminishes, the color of the rose will change.

This highlights that our perception of color is affected by how objects reflect and absorb light. Change the lighting in an area, and we’ll perceive the color of things in that setting differently.

How the Cornea, Pupil, and Lens Work Together to See Color

Illustration of how human eyes see with definition of the eyes anatomy

Now imagine the rose in a fully lit room once again. The rose petals will absorb some of the light in the room. But some of that light will also be reflected. When we look at the rose, we see that reflected light. This process begins within our eye’s cornea.

The cornea can be thought of as a satellite dish of sorts. It takes in the reflected light and sends it to our eye’s pupil. The pupil is the dark mass in the center of our eye. The expansion or dilation of our pupil controls the amount of light we take in. This light will then hit the lens in our eye.

The lens in our eye is quite similar to that in a pair of glasses — both lens types focus light. The lens in our eye focuses light to send it to the retina. Our retinas are about as thin as a razor blade. However, this deceptively small structure has some advanced functionality.

An Interplay Between Retina and Brain

Illustration of the visualization process of human color vision from seeing with the eyes to processing in the brain

The retina can be thought of as an extension of our brain. In fact, the retina is formed from brain tissue. That’s part of the reason why we’re able to take in visual information so quickly. Our eyes have a short and direct link to the brain. This is an important point because we need to process a lot of information to understand all the information we receive from the world.

Our retinas comprise 116 million specialized cells that work with light and color. This consists of 6 million cone cells processing visual information in brighter environments. We also have 110 million rod cells that work in lower-light environments. Each cone cell contains visual pigments that react to specific photonic wavelengths. Humans have four photopigments: one rod photopigment and three cone photopigments. They enable our eyes to differentiate between red, green, and blue.

When we look at the rose from before, the reflected light from the petals activates the red photopigment in our cone cells. Likewise, the rose’s stem activates the green photopigment in the eye’s cone cells. But now imagine that the rose is in a yellow vase. We’d see the color yellow due to the dual activation of red and green photopigments simultaneously.

But what happens if we dim the room’s lighting? Eventually, we’ll reach a point where the eye’s rod cells must handle things. Our rod cells are capable of more precise detail. This is partly why a black-and-white image tends to look sharper to us. However, rod cells lack the photopigments found in cones, so everything begins to look like a black-and-white picture as less and less light is present within an environment.

However, at the same time, we tend to see some color even when the lights have dimmed past the point where our cone cells are very active. The explanation for why that’s possible comes from the role of the brain and consciousness in our visual processing.

From the Human Eye to the Brain

Human eye with an image of a brain in the middle of the pupil and iris

There was a time when people thought of consciousness as a singular entity. Today we know that countless different neurological processes form our core identity. And most often, we are only aware of a little of what our brain is doing. This is especially true when it comes to vision.

We often assume that all the data taken in by the eyes will go directly into our conscious mind. It certainly feels that way. But in reality, the data from our eyes needs to be heavily processed before we can see it. And this helps explain why we sometimes see hints of color when we shouldn’t be physically able to do so. For example, in our earlier example of a rose, we can often still see hints of red even in near darkness. How is it possible to see hints of color in otherwise dimly lit scenes?

The answer is that we never directly observe color in the first place. Our eyes take in reflected light, but we aren’t conscious of the raw data. What we’re seeing is actually a heavily processed interpretation of data taken in by our eyes. Remember that we imagined the rose placed within a yellow vase?

When we look at the vase, we see the color yellow. But what really happens is that our eyes register stimulation in our cone’s green and red photopigments. Our brain creates the color yellow by integrating the dual stimulation of different photopigments. We don’t directly see anything — everything we have ever seen or will see results from unconsciously processed data in our brains.

It’s All in the Mind’s Eye

Illustration of visual perception in the human mind from the eyes and brain

We can better understand the mind’s role in vision by considering a few examples. One of the easiest to consider is how we see a single image when looking out onto a scene. Let’s return to the example of a red rose in a yellow vase. When we look at it, we see that singular image. Of course, we also take in the entirety of the environment around the flower. But take a moment to consider that we only see the single rose and the single vase. However, we have two eyes taking in that data simultaneously.

Each eye is taking in slightly different information about the scene before us. But we’re not conscious that we’re continually taking in two separate visual data feeds from the world. When our brain receives information from our eyes, it also integrates information from the two visual data sources.

This is why we don’t see two separate versions of a scene in front of us despite having two eyes. The information from each eye is unconsciously processed and essentially stitched together. And when our eyes miss something, our mind can even create illusions to fill in the blanks.

A Path Through the Blind Spots

Structure of the human eye and organization of the optic part of the retina

That we’re continually adding information to the data taken in by our eyes might initially seem strange. But consider the fact that each of our eyes has a blind spot. The point where nerve fibers pass from the retina to the back of our eyeball contains no photoreceptors.

This means that both eyes pass a signal to the brain, which essentially is missing information. But we aren’t conscious of any gaping holes in our vision. That’s because our mind extrapolates the most likely data to fill those blank spaces.

For example, our left eye might miss a pattern on the vase due to its blind spot. But our right eye might have seen the pattern. If that’s the case, then our subconscious can easily extrapolate what the left eye missed from data taken in by the right eye.

Color Consistency and the Unconscious Mind

Woman in red colored long dress standing on mountains enjoying view of rising sun and white fog below

A recent debate over dress color also offers an excellent example of how our mind fills in details our eye misses. The dress illusion stems from a situation where the same image will appear differently to various people. A picture of the same dress will appear to have different colors for different people.

This phenomenon also explains why we can see some colors in a dimly lit room. In the dress example, our minds are attempting to compensate for lighting. We’re not consciously aware that our mind is doing so. But when we see the lighting in the picture, our unconscious mind will often start to color correct for it. The same thing happens when we look at objects in a darkened environment.

We know that a rose has red petals. Therefore when there’s not enough light to register colors, our unconscious mind will often fill in that detail. We do see hints of red on the flower. However, this is only because our unconscious mind colorizes the black-and-white image our eyes see.

If we close our eyes and someone replaces the red rose with a different colored rose, we still see it as red. That’s because our unconscious processes supply the color entirely in the low light environment. We only see red in that situation because we expect to see red.

A Process of Co-Creation

Human hand holding glass ball in front of sunset symbolizing vision in the conscious and unconscious mind

As we examine human vision, we see just how complex it is. The fact that vision seems so straightforward from our subjective experience highlights how complicated that process is. It takes a lot of mental processing to turn so much data into something we don’t need to consider consciously. We seldom need to think about seeing the world. Instead, it all happens naturally.

In reality, our vision is a continual co-creation with the world. When we look at the beauty around us, it’s not just an inherent property of any given thing. We continually add to that beauty by painting the world in our minds. We create detail our eyes have missed and mentally compensate for lighting oddities without even being aware of it.

In reality, we should take more credit for beautiful sunsets or the gorgeous colors of a rose. Much of the beauty we perceive comes from the world outside of us. But much of that beauty is also due to our subconscious artistry, continually painting the world in a myriad of different colors. When we see beauty in the world, we’re also creating it at the same time.