Photo by Sharon McCutcheon / Unsplash

The science of colours


Look around you! What is the first colour you noticed? Red? Green? Yellow? Colours are everywhere. Animals use colours to hide from predators or attack prey. Human beings see colours every day right from the moment they wake up till they return to bed. Colours affect our moods, emotions and decisions even if we refuse to admit it. Thus, it is important to learn how colours may be affecting our lives and adjust them accordingly.

Meaning of colours

Human beings can only view colours with the help of light. Light is a form of electromagnetic energy that has a wavelength, which helps to determine colour. Light travels in waves. The difference between the two different peaks is termed wavelength. For humans, the visible spectrum has a wavelength between 400-700 meters of wavelength.

The light human beings see is just a small portion of the light spectrum called visible light. The other forms are gamma rays, UV rays, radio waves, microwaves and so on. Human beings are unable to see such rays but maybe that is a good thing. Imagine being in a public space where people have their radios turned on. If we had the ability to view the entire spectrum of light, then we would be able to see all the radio waves and microwaves which would be disturbing.

How humans perceive light

When light hits an object, two main things happened- absorption and reflection. The object absorbs a majority of the wavelengths and reflects the rest to our eyes. In our eyes, there are special tissues called retina which is made up of rods and cones. These cells respond differently to the different wavelengths and communicate it to the brain. Rods allow you to see in low light or in the dark while cones allow you to view colours in the presence of light.

The rods and cones transmit the electrical signals of the light through a channel-optic nerve to a region of the brain-thalamus. The thalamus repackages it to the visual cortex of the brain which is mainly responsible for appearances. It also interprets it in another region of the brain called the prefrontal cortex where the colour of the object together with other characteristics such as the shape of the object is interpreted by human beings. All these happen within a split of a second when you see an object.

Thus, the amount of wavelength will inform the brain about the type of colour. For instance, the brain will interpret wavelength around 400 as blue while interpreting 700 as red. As beautiful as colours are, not everyone can view them as a result of colour blindness.

Colour blindness

There are three different types of cones. Each one of the three different cones is sensitive to either blue, green or red. The presence or absence of any will determine how much colour a person can see. Colour blindness occurs when one or more than one type of cone is missing or non-functional in the retina.

A person who has all the three cones can see blue, green and red all the different shades related to such colours. This individual is termed a trichromatic.

A person who has only two of such cones can only see such two colours and their different shades. Such a person is termed a dichromatic. Examples of such combinations include:

1. Protanopia-the loss of red cones.

2. Deuteranopia-the loss of green cones.

3. Tritanopia-the loss of blue cones.

Other forms of colour blindness include:

4. Incomplete achromatopsia- the loss of 2 out of the 3 cones.

5. Complete achromatopsia – the loss of all three cones. They are also referred to as monochromatic. This means only the rods are working so they see objects as black and white.

There has been research which states that some women may have up to 4 different cones which give them the advantage of differentiating between millions of colours. Such individuals are known as tetrachromatic.

Colour blindness is caused by genetic mutations and can only be transferred from parents to offspring. Hence, if you do not have it now, you will not get it later.

Types of colours

Colours are generally grouped into warm, cold and neutral colours.

Warm colours include red, orange and yellow.

Cold colours include blue, green and purple.

Neutral colours are black, white or grey.

Impact of colours on humans

The impact of colour is much more powerful than we have realized. Companies use colours to attract their target audience, pharmacists consider colours in the manufacturing of drugs, schools and offices use colours during teachings and workings, and hospitals and surgical tools and equipment all employ colours to achieve a certain effect. In addition, some prisons are painted with a certain type of colour to tame unruly prisoners. Colours affect the mood and feel of the environment. Using warm colours such as red, and orange can make a room feel cozy and smaller. Cold colours make a room feel cold and spacious.

· Red is an aggressive colour but shades of red such as pink reduce the aggressive nature of red. Red is used to energize the body and mind. It increases metabolism and stimulates appetite. Thus, it can be used in restaurants, living rooms and dining areas. Wearing red will draw attention to yourself. Red is also used to designate danger or stop signs in the environment.

· Yellow is used to make people feel cheerful. It can be used in the kitchen, dining rooms and bathrooms. However, too much yellow can irritate the eyes. In a room, yellow should be used in a comforting way.

· Blue allows the mind to focus. Dark blue evokes a feeling of sadness while light blue can evoke calmness. Blue is recommended for the study room, offices, bedrooms and washrooms. Companies tend to use light blue as it tends to give a calming effect such as Facebook and Twitter. Doctors wear gowns made of light blue to assure patients and calm them.

· Green is a very restful colour. It is relaxing, healing and optimistic. It can be used in most rooms.

· Purple is a favourite colour by many. It exudes creativity, royalty and class.

· Black shows sophistication, elegance and class. It is used by most bachelors. Black is also used by many teenagers to hide their emotions. Wearing a black dress will make you look slimmer.

· White is seen as fresh and pure. Thus, most brides wear white to express innocence and purity. Men who wear white are termed more attractive. White is used to show simplicity.

· Brown is a down to earth colour. Most people do not prefer brown as it usually is seen as old-fashioned.

Colours undoubtedly have impacts on our health, our mood for the day, the workplace and a night of sound sleep. The next time you are obliged to use colour, choose wisely!


  1. verywellMIND.  Colour psychology. Retrieved from is a powerful communication,%2C increased metabolism%2C and eyestrain.
  2. Lets talk science. How we see colour. Retrieved from



A young lady who is excited to influence the society and world with the knowledge she has acquired.