How and Why We See Colors

When it comes to colors, it’s impossible to not talk about light. It’s one of the most crucial issues, and understanding this area will help you grasp how color is formed and why we see things in the first place.

For many years, the nature of light has been perplexing and difficult to comprehend. We now know that light acts both as a wave and a stream of particles. A wave-particle duality is the term used to describe this phenomenon.

Visible light is a form of electromagnetic radiation with a wavelength between 380 and 780 nanometers. The basic colors are a combination of seven simple single colors that produce white light.

Color is the result of light being reflected or emitted by different things. You must have light to see color. Some colors bounce off an object and others are absorbed by it when light shines on it. The colors that are sent off or reflected by an object are the only ones that our eyes can detect.

When they decompose, they may be seen in the form of the well-known seven colors of the rainbow. On sunny days when it rains, this effect can be observed in the sky. When water droplets fall and strike one another, they create a prism that splits white light into its components.

Each color is assigned to a distinct wavelength range. The longest wavelength (635-770 nm) is red, while the shortest wavelength (380-450 nm) causes people to see purple.

The primary colors that we are exposed to are shown below. If the wave is between two adjacent ranges, transitional colors are produced.


Color Wavelengths
Color Wavelength(nm)
Red 635 – 770
Orange 590 – 635
Yellow 565- 590
Green 520 – 565
Cyan 500 – 520
Blue 450 – 500
Purple 380 – 450


Why Do Humans See Colors?

Now that we know that certain electromagnetic wavelengths have a defined color, let us consider why we see colorful objects. We know now that certain electromagnetic wavelengths will defined it’s color, let’s now understand why we even see colors in the first place.

The sensitivity of the eye’s receptors to a light wavelength is responsible for color vision. We can perceive colors in things like crayons and flowers since they reflect and absorb the rays of light that strike them.

The objects we see around us, on the other hand, do not shine with their own light and reflect only particular electromagnetic wavelengths from the visible spectrum after absorbing all the others.

We perceive a specific color due to the radiation that is reflected from an object’s surface and reaches our eyes.

For a deeper understanding of this mechanism, consider an example. Yellow daisies are able to absorb all wavelengths of electromagnetic radiation, with the exception of those that produce yellow light.

When a wave reaches the eye, it is reflected in waves of this length, causing the eye to see yellow. When an item is white, it indicates that all white light is reflected from it. Black things instead absorb all wavelengths in the visible light spectrum.

How do Humans See Colors?

Without eyes, the ability of electromagnetic waves to be absorbed and reflected in order for us to perceive the world in color would not be possible.

They are extremely sensitive organs of the sense of sight, which participate in the creation of images, commonly known as vision. Eyes are very sensitive organs of the sense of sight, which help in the production of images, or what is know as vision.

We must examine the structure of the eye to understand why we consider electromagnetic waves to be colors. The visual organ, which includes rods and cones, has photosensitive receptors.

Retina is the back of the eye’s surface, where photosensitive cells may be found. Rod cells are used to interpret form and movement. They’re so sensitive that a single photon can set them off. Cones, on the other hand, are involved in the perception of colors.

There are three different types of cones in the human eye, each one reacting to a different wavelength. As a result, they enable us to see red, blue, and green hues. All three types of cones respond to the stimulus if receptors register intermediate wavelengths, giving rise on the brain’s perception of an intermediate color made up of three basic colors.

How Image Creation Works

Visible light is simply electromagnetic waves in the 380-780 nm wavelength range. Light that strikes an object is partially absorbed and partly reflected. Finally, the electromagnetic wave reflected from the object is transmitted to the receptors in the eye, which are cones and rod cells in the retina where a reduced and upside down image is generated.

The receptors transmit an impulse to the brain, in which the data is interpreted and an image of the object is generated. Everything happens at a breakneck speed that you can observe by looking around. Our eyes immediately register and process colors, resulting in an image.

The eye, which is the most amazing sight organ in the world, distinguishes a wide range of hues. Literature claims that there are millions of them. It’s worth noting that color isn’t derived from light; rather, it’s an impression caused by a certain wavelength of electromagnetic radiation bouncing off into the eyes and registered by the brain.

The experience of seeing a color is fleeting, and it isn’t stored in our memory. As a result, recognizing the identical hue again because we lack a color pattern to which we may compare it is quite tough. It’s vital to remember that the meaning of color by various eyesight may be ambiguous and imprecise since color vision is subjective.

Color Description and Assessment

Color is impossible for the human eye to judge, but colorimeters and spectrophotometers are used to precisely assess it. Instrumental methods allow you to express color in numerical form based on a standard calculation utilizing colorimeters or spectrophotometers.

The International Commission on Illumination (CIE) created the mathematical color record, which is comparable with the visual assessment.

Color is described with three attributes:

  • Hue, is the feature that depends on the radiation of a specified wavelength, that is in turn captured by the receptors in the human eye. This will allow us to see a color like green, blue, red, etc. Colors that have a hue can be referred as a chromatic color.
  • Brightness, color intensity, is the objects sensitivity to radiation intensity that causes a color to appear. Luminance is the measurement of color brightness in a given situation. In daylight, the yellow-green hue has the highest luminance at 555 nm, and in darkness (when it’s dark), it has a wavelength of 510 nm that corresponds to the blue-green color.
  • Saturation refers to mixing a color with black, grey or white. Pastel colors are considered unsaturated because they contain so much white color.

Hue, brightness and saturation are also standardized by the CIE system, making it possible to describe a color using these three attributes.

Color Tolerance

Because a perfect color match on an industrial scale is impossible, it’s typical to establish color tolerance ranges. Differences in the supply of raw materials for manufacturing that have been dyed may be responsible for the lack of 100% color matching.

Another cause is color variation during follow-up procedures in the production. In fact, each batch of goods has a unique color variance. The degree of this error is the distance between acceptable and almost matching colors. Individual contractors establish the criteria for color acceptability.

RGB model

The RGB model is another way to express colors. It’s a method for representing color space in a coordinate system using the RGB acronym, which stands for English names of colors: R – red, G – green, B – blue.

Any color that is produced by mixing three beams of light in these hues in specific proportions and amounts has been created. This model can only explain how the color sensation in the human brain is generated.

Unfortunately, the model has a few drawbacks – for example, it does not explain why lighter color or pure white is not produced when bright colors are mixed together. It is important to bear in mind that the RGB model is only a theoretical one, and its reproduction depends on a specific device.

CMYK Model

The CMY color model, in practice, is not a sufficient foundation for obtaining all of the hues recognized by the human eye. Mixing together the components of the model—blue (cyan), red (magenta), and yellow—will never result in black.

That is why, when we discuss a CMYK model enhanced by the black color K–the key color (black), we are referring to a four-color model. It’s the most frequently used color model for multi-color prints or computer graphics.

The CMYK color model is a method of representing colors electronically. The four primary colors can be combined to make various colors using the right proportions.

Color Description and Assessment

Now that you know the most popular color model evaluation systems, it’s reasonable to assume that combining RGB model colors with CMYK model colors should produce all possible hues.

The answer, on the other hand, is no. What’s the problem? Because human eyes do not respond linearly and dyes and colorful materials aren’t flawless. As a result, various masking techniques are employed in practice. The techniques to account for these flaws are known as color production, which include, among other things, printing, industrial dyeing, and the creation of crayons, paints, and varnishes.

The difference, it appears, is that the goal was not to generate a specific hue but rather to communicate it – what it should look like. How can we define and name a color in such a way that everyone understands it? This problem has yet to be addressed, although perhaps in the future there will be a universal color coding system developed to address.