Problems of subjective color perception

Subjective perception of colors. Once upon a time, two interlocutors were arguing about colors. One of them claimed that all people see the same, while the other disagreed. "Is your red the same as my red?" "Maybe you see "my" blue instead of red?"...And the debate continued.

You may find these things funny, amusing, or even pointless. After all, we all see the same thing. Huh…it's all a lot more complicated than we might think based on this fictional debate. But maybe we really do see colors differently? Let's leave aside anomalies such as color blindness and similar conditions. We can say with great certainty that our eyes received the same light as the interlocutor's in a certain situation, i.e. also the colors, since they are part of the light. The part that we can see with our visual receptors. Somewhere from 380 to 750 nm wavelength. So if our eyes are healthy and similar to others, then so be it we are watching pretty much the same. Is that true?

What is the truth?

The difference, of course, is the color we perceive. After all, we see with our eyes, but we see with our brains. Let's start by following the trail of this light. As is known There are two types of photo sensor cells: rods and plugs. Rod-shaped cells detect shading and shapes, and are needed for peripheral and night vision. Plugs are important for perceiving details in good light and the perception of the colors of objects, but they perform their task worse in weaker lighting and in the dark. Rods and cones are distributed throughout the entire area of the retina except at the point where the optic nerve connects to the brain. The optic nerve transmits information received from the retina to the brain, which turns it into an image that we see. But that's where the uniformity ends. Each individual has his own, subjective system that translates this light into a visible image, and because our brain is a wonderful machine that perfectly responds to different situations and psychophysical states - this is what evolution brought so that we could survive - we also see differently in different situations. At the same time, there is also an emotional component that is the result of our experiences and also contributes to individual perception.

An additional limitation is the ability of our eyes. When looking at certain colors, the sensors (pins and rods) can become saturated and the brain receives wrong information. For example, if we stare at a green sheet of paper for a while, and then look at a white wall, will we still see the shape of that sheet for a few seconds, but in a reddish color? Why not in green, if we were staring at a green leaf? This is partly the fault of our plugs and sticks, which have become tired, and partly it is the fault of the brain, which tries to compensate the oversaturation with the opposite color, which in the case of green is red. So the brain sees oversaturation and tries to correct/balance it. Therefore, it is also subjectively difficult to determine a neutral white color, because our "processor" tries to compensate for any deviation and does so constantly without our awareness. We can also show this with an example: when we step into a room that is illuminated by "warm" light, we will also perceive it. Over time, however, this feeling will disappear and we will think that the light is white. So the brain adjusted and found a new center reference for white.

Is our visual system similar to a photographic camera?

Not at all, although it has very similar components that can be compared to each other:

Eyeball - lens
Eye muscles - auto focus
Eye lens - the lens system in the objective
Retina - sensor/film
The brain is the processor

As we can see, in modern times, with the use of a digital camera and a processor, we have come a step closer because algorithms and sensors help us process light into what we would like to see. Let's say shooting in artificial light. With an analog camera, we had to use different filters to balance the light, but now this is done by a processor that appropriately processes the input signal. Just like our brains.

Conclusion

So we see colors really differently. This is partly the fault of the circumstances, and partly the fault of the psychophysical state at the time of viewing. Through evolution, the human (and of course animal) visual system has perfectly adapted to various situations that helped the individual to survive. Some species see, say, less detail and more colors, even beyond our human perceptions. Others, however, have specialized in low-light conditions, and colors are not that important to them. If we stick to our - human perception of colors, we are somewhere in the golden middle. The system works perfectly in nature, but when we are faced with work where colors are important in different situations, such as photography, printing, the automotive industry, ... we fail there. Since the eyes/brain can deceive us in such a way, it is important that when working with colors we use instruments that are independent of our perception - spectrometers, calibrated light, color charts...only in this way will we get repeatable results that will not depend on subjective looks.