Colour Theory 101

I’m not too sure about you, but I always dread making posters or slideshows, especially once it comes down to trying to figure out which colours to use, or which look the best together. The possibilities are endless – but somehow, whenever I try to forge a colour palette, it winds up looking like a funky abstract art piece. 

So, after doing some research, I’ve compiled some information on colour theory and how to apply it to real life situations, which I’ve then compressed into a small ‘101 on colour’ for you!

Let’s first recollect our memories of art class and discuss the basics of colour.

Do you remember primary, secondary, and tertiary colours? 

These make up the foundations of colour theory!

First are the primary colours: red, yellow and blue. These colours cannot be created by mixing other colours. These colours anchor your design in a general colour scheme – but don’t feel limited to only using tints of these colours. 

Next we have our secondary colours, which are formed by two primary colours. There are three secondary colours: orange, purple, green, which are formed by the following combinations:

  • Red + Yellow = Orange
  • Blue + Red = Purple
  • Yellow + Blue = Green

These colours can only be made when the primary colours are in their purest form/hue.

And finally, we have tertiary colours. These colours are made when a primary colour is mixed with a secondary colour. From here onwards, the idea of colour starts to get quite complex. Here are a few colour combinations that belong to the tertiary colour model.

  • Yellow + Orange = Yellow-Orange (Amber)
  • Blue + Purple = Blue-Purple (Violet)
  • Blue + Green = Blue-Green (Teal)
  • Red + Purple = Red-Purple (Magenta)

Additive and Subtractive Colour Theory

If you have played around with colour in a computer program, you’ve most likely seen the module RGB and CMYK. 

But what do these modules actually mean?

CMYK – The Subtractive Colour Model

CMYK stands for Cyan, Magenta, Yellow and Key (Black). These colours are typically used in printing and are often the colours used in printer ink cartridges.

CMYK is a subtractive colour model.This means that the more colours you add, the closer you get to black, and the more colours you subtract, the closer you will get to white – hence the name ‘subtractive colour model.’

RGB – The Additive Colour Model

RGB stands for Red, Green, and Blue. You will most likely recognise these as the colour of light, and as the colour used for electronic displays. 

This is the additive colour model of light waves. This means that the more colours you add, the closer you will get to white.

The RGB and CMYK values in your colour module will typically be listed when producing colour on a computer. In real life, you can find colours with either model, and the other model will adapt. However, many web applications simply provide you with the RGB values or a HEX code – which is the code given to colours in CSS and HTML. So, RGB is probably your best option for selecting colours when developing digital images, or for the web. If you ever require designing printed products, you can always convert it to CMYK and make changes. 

The Colour Wheel

The colour wheel is a great tool for choosing colour schemes. In a circular graph, the colour wheel charts the primary, secondary, and the tertiary colours (as well as their respectable hues, tints, tones and shades). This in turn makes visualising colours easier. It can help you choose colour schemes by easily allowing you to see the relationship between each colour.

The colour wheel gives you opportunities to create brighter, lighter, softer, and darker colours by incorporating white, black, and grey into the original colours when selecting a colour scheme.


The term ‘hue’ refers to a colour or shade. All primary, secondary, and tertiary colours are hues. When mixing two primary colours to produce a secondary colour, it’s crucial to consider hues. The hue of a secondary colour cannot be achieved if you do not combine hues of the two primary colours you are mixing. This is due to the fact that a hue contains only the purest colours. By combining two fundamental colours that contain additional tints, tones, and shades, you are essentially adding more than two colours to the mix and relying on the compatibility of more than two colours to get your desired colour. 


Shade is a term that refers to how dark or light a hue is. Shade is often seen when you add black to a colour; the darker the shade, the more black that has been added to a certain hue.


Contrary to shade, tint is the mixture of a hue with white. Instead of adding black to a hue, white is added, making the hue softer and lighter in colour.


For saturation or tone, black and white is added to a hue. Saturation will often be used in digital images through editing in order to  alter the intensity of a hue.

Types of Colour Schemes

There are a variety of different colour schemes. Let’s examine a few examples:


  • Monochromatic 

Monochromatic schemes use a single hue, but use varying tints and shades to produce a harmonious look and feel. It lacks the contrast of colour, but gives off a minimalistic and very polished look, as well as giving the opportunity to change to different shades and tints.

  • Complementary

Complementary colours are a pair of colours that are positioned directly opposite each other in the colour wheel. This also includes their varying hues, tints and shades. This colour scheme provides a great amount of contrast in colour, due to the fact that they are directly opposite each other in the colour wheel. Therefore, you will have to be mindful when using this colour scheme.

  • Analogous 

Analogous colours is the pairing of a main colour with two to four main colours on either side. This does not create a great deal of colour contrast, and is generally used for a softer and more compatible look. It is best to use this scheme when designing images rather than infographics, as the elements typically blend in better.

  • Triadic

Similar to the complementary colour scheme, the triadic colour scheme creates  highly contrasting colour palettes. This scheme is created by selecting three colours that are placed around the colour wheel with equal distance between each other. Triadic palettes are useful if you want to introduce a high variation of colours and make them stand out to the eye. But, it can be overwhelming if they are used in only one hue. Because of this, it is better to use this scheme in infographics or pie charts, as the contrast helps to create a distinct comparison between elements. 

  • Square

The square colour scheme is much the same as the triadic colour scheme, however this time, four colours which are equal distance apart from each other are chosen, creating a square shape – hence its name. This is also a scheme that involves very high contrast between colours, so it is better to choose one main colour and use the other three as accents.

There are numerous colour theories that can be applied in everyday life. But when it comes to choosing colours, understanding the theory behind colour in a deeper sense is key. It can do wonders with the way you choose your colour palettes! Keeping these simple theories in mind can simplify the process of making posters, slideshows, designing, and in my case, figuring out which colours to use!


Written by Samadhi Samarathunga and edited by Sophia Oblefias. Published on 20/8/23. Header image by Felix Yang.

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